Journal

JCO Precision Oncology

Papers (57)

Serial Circulating Tumor DNA Sequencing to Monitor Response and Define Acquired Resistance to Letrozole/Abemaciclib in Endometrial Cancer

PURPOSE In a phase II study, letrozole/abemaciclib demonstrated an objective response rate of 30% and a median progression-free survival (PFS) of 9.1 months in recurrent estrogen receptor–positive endometrial cancer (EC). While tissue-based tumor profiling revealed several mechanistically relevant candidate baseline genomic predictors of response, circulating tumor DNA (ctDNA) is a less invasive alternative to monitor therapeutic efficacy and define acquired resistance. METHODS Serial plasma specimens were obtained at baseline, C2D1, C3D1, C8D1, the time of objective response, and the time of progression. Samples were analyzed using the Guardant Reveal assay to assess methylation-based tumor fraction (TF), with the Guardant360 assay providing genotyping of >700 genes in samples with detectable ctDNA. Treatment response was assessed using a measure of the relative change in TF pre- versus on-treatment. RESULTS A total of 99 of 102 (97%) samples from 28 patients were successfully analyzed. Patients with above median baseline TF exhibited worse median PFS (2.0 months v 16.5 months, P < .005, hazard ratio [HR], 24.1) and worse overall survival (OS) (10.7 months v not yet reached, P < .005, HR, 14.8). Patients with molecular response (MR) after the first or second cycle of letrozole/abemaciclib therapy had significantly better median PFS and OS regardless of the cutoff used for definition of MR. ctDNA analysis of postprogression specimens identified several acquired genomic alterations associated with resistance to letrozole/abemaciclib therapy in more than half of the patients, including PI3K pathway, receptor tyrosine kinase ( FGFR1 , 2 and ERBB2 alterations), cell cycle pathway ( RB1 and CCNE1 alterations), and ESR1 and MAPK pathway alterations. Two of the three patients with mismatch repair–deficient ECs acquired ESR1 mutations at the time of progression. CONCLUSION Baseline and on-treatment ctDNA dynamics may provide an early indication of benefit from letrozole/abemaciclib in EC. ctDNA at the time of progression may identify resistance alterations that may inform subsequent therapy.

Identification of Targetable EGFR Mutations in Ovarian Cancer

PURPOSE EGFR mutations are classically seen in non–small cell lung cancers (NSCLCs), and EGFR-directed inhibitors have changed the therapeutic landscape in patients with EGFR -mutated NSCLC. The real-world prevalence of EGFR -mutated ovarian cancers has not been previously described. We aim to determine the prevalence of pathogenic or likely pathogenic EGFR mutations in ovarian cancer and describe a case of EGFR -mutated metastatic ovarian cancer with a durable response to osimertinib, an EGFR-directed targeted therapy. METHODS Retrospective review of 33,850 molecularly profiled ovarian cancer samples from real-world patients who underwent next-generation sequencing (NGS) of DNA between 2016 and 2025. EGFR -mutated cases were defined as those harboring known pathogenic or likely pathogenic mutations based on the EGFR genomic alteration discovered by Caris. RESULTS Of 33,850 patients, 27 (0.08%) harbored a genomic alteration in the EGFR gene that was pathogenic or likely pathogenic, including EGFR exon 20 mutation (n = 12, including five patients with EGFR T790M mutation), EGFR L858R (n = 3), and an EGFR exon 19 deletion (n = 2). Only one patient was treated with osimertinib, a third-generation EGFR-inhibitor, and achieved a durable objective response for over 17 months. CONCLUSION Ovarian cancer driven by an oncogenic EGFR mutation is a rare occurrence, yet it is an actionable molecular target with EGFR-directed inhibitors. This underlies the potential value of comprehensive NGS in the management of ovarian cancer for discovering actionable genomic alterations.

Incorporating Continuous Mammographic Density Into the BOADICEA Breast Cancer Risk Prediction Model

PURPOSE Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA v7) predicts future breast cancer (BC) risk using data on cancer family history (FH), genetic markers, questionnaire-based risk factors, and mammographic density (MD) measured using the four-category Breast Imaging Reporting and Data System (BIRADS) classification. However, BIRADS requires manual reading, which is impractical on a large scale and may cause information loss. We extended BOADICEA to incorporate continuous MD measurements, calculated using the automated Volpara and STRATUS tools. METHODS We used data from the Karolinska Mammography Project for Risk Prediction of Breast Cancer cohort (60,276 participants; 1,167 incident BC). Associations between MD measurements and BC risk were estimated in a randomly selected training subset (two thirds of the data set). Percent MD residuals were calculated after regressing on age at mammography and BMI. Hazard ratios (HRs) were estimated using a Cox proportional hazards model, adjusting for FH and BOADICEA risk factors, and were incorporated into BOADICEA. The remaining one third of the cohort was used to assess the performance of the extended BOADICEA (v7.2) in predicting 5-year risks. RESULTS The BC HRs per standard deviation of residual STRATUS density were estimated to be 1.48 (95% CI, 1.33 to 1.64) and 1.41 (95% CI, 1.27 to 1.56) for pre- and postmenopausal women, respectively. The corresponding estimates for Volpara density were 1.27 (95% CI, 1.15 to 1.40) and 1.38 (95% CI, 1.25 to 1.54). The extended BOADICEA showed improved discrimination in the testing data set over using BIRADS, with a 1%-4% increase in AUC across different combinations of risk factors. On the basis of 5-year BC risk with MD as the sole input, approximately 11% of the women were reclassified into lower risk categories and 18% into higher risk categories using the extended model. CONCLUSION Incorporating continuous MD measurements into BOADICEA enhances BC risk stratification and facilitates the use of automated MD measures for risk prediction.

Geneva Homologous Recombination Deficiency Test Is Predictive of Survival Benefit From Olaparib and Bevacizumab Maintenance in Ovarian Cancer

PURPOSE The ability of the Geneva homologous recombination deficiency (HRD) test to predict progression-free survival (PFS) in patients with high-grade ovarian cancer treated with poly (ADP-ribose) polymerase inhibitors has been demonstrated. Its performance with respect to overall survival (OS) has not been assessed yet. METHODS Using the final results of the PAOLA-1/ENGOT-ov25 phase III clinical trial with a median follow-up of 5 years, we evaluated the Geneva HRD test on 468 samples as part of the ENGOT HRD European Initiative. Results were evaluated in terms of final PFS and OS in the olaparib + bevacizumab and placebo + bevacizumab arms and compared with the Myriad MyChoice HRD test. RESULTS Final PFS was consistent with previously published data and confirmed the predictive value of the Geneva HRD test with a hazard ratio (HR) of 0.41 (95% CI, 0.30 to 0.57) for HRD-positive patients. The results for OS showed a HR of 0.56 (95% CI, 0.37 to 0.85) for HRD-positive patients and 1.6 (95% CI, 1.1 to 2.3) for HRD-negative patients. These results are consistent with those observed with the Myriad test, including the negative OS trend in the HRD-negative subgroup treated with olaparib + bevacizumab (HR, 1.2 [95% CI, 0.83 to 1.8]). A subgroup analysis of patients with intermediate HRD scores showed that the normalized large-scale state transition score used by the Geneva HRD test had both predictive and prognostic value. CONCLUSION The Geneva HRD test predicts PFS and OS benefit from olaparib + bevacizumab. The potential detrimental effect of olaparib + bevacizumab on OS in the HRD-negative population is hypothesis-generating and needs to be confirmed prospectively.

AlphaMissense for Identifying Pathogenic Missense Mutations in DNA Damage Repair Genes in Cancer

PURPOSE AlphaMissense is a new artificial intelligence–based approach to predicting the pathogenicity of missense variants. However, whether its predictions can be directly applied to clinical decision making remains unclear. This study aimed to evaluate the accuracy of AlphaMissense predictions for DNA damage repair (DDR) genes using genomic and clinical characteristics. METHODS Sequencing data from 56,965 patients with cancer who underwent Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) testing between April 2015 and March 2023 and data from The Cancer Genome Atlas (TCGA)/Pan-Cancer Analysis of Whole Genomes (PCAWG) were analyzed. AlphaMissense pathogenicity was evaluated in six commonly mutated DDR genes. Missense mutations were classified into three categories on the basis of AlphaMissense and OncoKB: known pathogenic, newly identified pathogenic by AlphaMissense, or benign. RESULTS In the MSK-IMPACT cohort, 1,182 (17.5%) of 6,743 unique DDR gene missense mutations were newly identified as pathogenic. In breast, ovarian, pancreatic, and prostate cancers, homologous recombination (HR)–deficiency signatures were more common in tumors with new pathogenic missense mutations in BRCA1/2 , PALB2 , and RAD51C than in benign missense mutations (66.7% v 35.2%, P = .021). In the TCGA/PCAWG data set, HR-deficiency signatures were also more frequent in tumors with new pathogenic mutations than in wild-type (46.2% v 19.2%, P = .036). For tumors with POLE missense mutations, there were no significant differences in tumor mutation burden and POLE-associated signatures between new pathogenic and benign mutations. Patients with new pathogenic ATM missense mutations had fewer TP53 mutations (30.5% v 54.6%, P < .001) and showed improved irradiated tumor control (hazard ratio, 0.58 [95% CI, 0.35 to 0.95]; P = .03) compared with those with benign missense mutations. CONCLUSION Our findings suggest that AlphaMissense can help identify previously unknown pathogenic DDR gene mutations, but its accuracy is gene-dependent. AlphaMissense prediction still requires additional confirmation with clinical and functional validation.

Constitutional Epimutations: From Rare Events Toward Major Cancer Risk Factors?

Constitutional epimutations are epigenetic aberrations that arise in normal cells prenatally. Two major forms exist: secondary constitutional epimutations (SCEs), associated with cis -acting genetic aberrations, and primary constitutional epimutations (PCEs), for which no associated genetic aberrations were identified. Some SCEs have been associated with risk of cancer ( MLH1 and MSH2 with colon or endometrial cancers, BRCA1 with familial breast and ovarian cancers), although such epimutations are rare, with a total of <100 cases reported. This contrasts recent findings for PCE, where low-level mosaic BRCA1 epimutations are recorded in 5%-10% of healthy females across all age groups, including newborns. BRCA1 PCEs predict an elevated risk of high-grade serous ovarian cancer and triple-negative breast cancer (TNBC) and are estimated to account for about 20% of all TNBCs. A similarly high population frequency is observed for mosaic constitutional epimutations in MGMT , occurring as PCE or SCE, but not in MLH1 . Contrasting BRCA1 and MLH1 , a potential association with cancer risk for MGMT epimutations is yet unclear. In this review, we provide a summary of findings linking constitutional epimutations to cancer risk with emphasis on PCE. We also highlight challenges in detection of PCE exemplified by low-level mosaic epimutations in BRCA1 and indicate the need for further studies, hypothesizing that improved knowledge about PCE may add significantly to our understanding of cancer risk, carcinogenesis, and potentially development of other diseases as well.

Niraparib, Dostarlimab, and Bevacizumab as Combination Therapy in Pretreated, Advanced Platinum-Resistant Ovarian Cancer: Findings From Cohort A of the OPAL Phase II Trial

PURPOSE To report the results of OPAL (ClinicalTrials.gov identifier: NCT03574779 ) cohort A, a single-arm substudy of niraparib plus dostarlimab and bevacizumab for the treatment of advanced, platinum-resistant ovarian cancer (PROC). METHODS Participants with PROC who received 1-2 previous lines of therapy were treated with niraparib (200 or 300 mg once daily), dostarlimab (500 mg once every 3 weeks for four 21-day cycles, followed by 1,000 mg once every 6 weeks), and bevacizumab (15 mg/kg once every 3 weeks). The primary end point was investigator-assessed objective response rate (ORR) per RECIST v1.1. Safety was also assessed. Exploratory biomarker end points included evaluation of changes in the tumor molecular profile and microenvironment using baseline and on-treatment tumor samples. RESULTS Of 41 enrolled participants (median age, 66.0 years [range, 37-83 years]), 9.8% had tumors that were BRCA-mutated, 19.5% were homologous recombination (HR)–deficient, and 17.1% were HR repair (HRR)–mutated. As of the cutoff date, all participants discontinued treatment. The ORR was 17.1% (80% CI, 9.8 to 27.0), including one complete response (2.4%); the disease control rate was 73.2% (80% CI, 62.3 to 82.2). Two participants withdrew before first postbaseline scan because of adverse events (AEs). Grade ≥3 treatment-emergent AEs were reported in 92.7% of participants, with the most common being hypertension (26.8%). Response was not correlated with BRCA, HRR, HR deficiency (HRD), or PD-L1 status. Changes suggesting immune activation were observed in on-treatment samples after triplet therapy. CONCLUSION Results demonstrated modest activity of niraparib, dostarlimab, and bevacizumab in participants with PROC, many of whom had prognostic factors for poor treatment response. Most participants with response were bevacizumab-naïve. No association was found with HRD, BRCA, or PD-L1 status. AEs were consistent with previous monotherapy reports, except that hypertension was reported more frequently.

Combined Transcriptome and Circulating Tumor DNA Longitudinal Biomarker Analysis Associates With Clinical Outcomes in Advanced Solid Tumors Treated With Pembrolizumab

PURPOSE Immune gene expression signatures are emerging as potential biomarkers for immunotherapy (IO). VIGex is a 12-gene expression classifier developed in both nCounter (Nanostring) and RNA sequencing (RNA-seq) assays and analytically validated across laboratories. VIGex classifies tumor samples into hot, intermediate-cold (I-Cold), and cold subgroups. VIGex-Hot has been associated with better IO treatment outcomes. Here, we investigated the performance of VIGex and other IO biomarkers in an independent data set of patients treated with pembrolizumab in the INSPIRE phase II clinical trial (ClinicalTrials.gov identifier: NCT02644369 ). MATERIALS AND METHODS Patients with advanced solid tumors were treated with pembrolizumab 200 mg IV once every 3 weeks. Tumor RNA-seq data from baseline tumor samples were classified by the VIGex algorithm. Circulating tumor DNA (ctDNA) was measured at baseline and start of cycle 3 using the bespoke Signatera assay. VIGex-Hot was compared with VIGex I-Cold + Cold and four groups were defined on the basis of the combination of VIGex subgroups and the change in ctDNA at cycle 3 from baseline (ΔctDNA). RESULTS Seventy-six patients were enrolled, including 16 ovarian, 12 breast, 12 head and neck cancers, 10 melanoma, and 26 other tumor types. Objective response rate was 24% in VIGex-Hot and 10% in I-Cold/Cold. VIGex-Hot subgroup was associated with higher overall survival (OS) and progression-free survival (PFS) when included in a multivariable model adjusted for tumor type, tumor mutation burden, and PD-L1 immunohistochemistry. The addition of ΔctDNA improved the predictive performance of the baseline VIGex classification for both OS and PFS. CONCLUSION Our data indicate that the addition of ΔctDNA to baseline VIGex may refine prediction for IO.

Rate of Pathogenic Germline Variants in Patients With Lung Cancer

PURPOSE Germline genetic testing (GGT) is now recommended for all patients diagnosed with ovarian or pancreatic cancer and for a large proportion of patients based solely on a diagnosis of colorectal or breast cancer. However, GGT is not yet recommended for all patients diagnosed with lung cancer (LC), primarily because of a lack of evidence that supports a significant frequency of identifying pathogenic germline variants (PGVs) in these patients. This study characterizes GGT results in a cohort of patients with LC. METHODS We reviewed deidentified data for 7,788 patients with GGT (2015-2022). PGV frequencies were compared to a control cohort of unaffected individuals. GGT results were stratified by genomic ancestry, history of cancer, and PGV clinical actionability per current guidelines. RESULTS Of all patients with LC, 14.9% (1,161/7,788) had PGVs. The rate was similar when restricted to patients with no cancer family history (FH) or personal history (PH) of other cancers (14.3%). PGVs were significantly enriched in BRCA2, ATM, CHEK2, BRCA1, and mismatch repair genes compared with controls. Patients of European (EUR) genomic ancestry had the highest PGV rate (18%) and variants of uncertain significance were significantly higher in patients of non-EUR genomic ancestry. Of the PGVs identified, 61.3% were in DNA damage repair (DDR) genes and 95% were clinically actionable. CONCLUSION This retrospective study shows a LC diagnosis identifies patients with a significant likelihood of having a cancer-predisposing PGV across genomic ancestries. Enrichment of PGVs in DDR genes suggests that these PGVs may contribute to LC cancer predisposition. The frequency of PGVs among patients with LC did not differ significantly according to FH or PH of other cancers.

Combining Homologous Recombination-Deficient Testing and Functional RAD51 Analysis Enhances the Prediction of Poly(ADP-Ribose) Polymerase Inhibitor Sensitivity

PURPOSE To meet the urgent need for accessible homologous recombination-deficient (HRD) test options, we validated a laboratory-developed test (LDT) and a functional RAD51 assay to assess patients with ovarian cancer and predict the clinical benefit of poly(ADP-ribose) polymerase inhibitor therapy. METHODS Optimization of the LDT cutoff and validation on the basis of samples from 91 patients enrolled in the ENGOT-ov24/NSGO-AVANOVA1&2 trial (ClinicalTrials.gov identifier: NCT02354131 ), previously subjected to commercial CDx HRD testing (CDx). RAD51 foci analysis was performed and tumors with ≥five foci/nucleus were classified as RAD51-positive (homologous recombination-proficient). RESULTS The optimal LDT cutoff is 54. Comparing CDx genome instability score and LDT HRD scores show a Spearman's correlation of rho = 0.764 ( P < .0001). Cross-tabulation analysis shows that the sensitivity of the LDT HRD score is 86% and of the LDT HRD status is 91.8% (Fisher's exact test P < .001). Survival analysis on progression-free survival (PFS) of LDT-assessed patients show a Cox regression P < .05. RAD51 assays show a correlation between low RAD51 foci detection (<20% RAD51+ cells) and significantly prolonged PFS ( P < .001). CONCLUSION The robust concordance between the open standard LDT and the CDx, especially the correlation with PFS, warrants future validation and implementation of the open standard LDT for HRD testing in diagnostic settings.

Endometrial Cancer Risk Among Germline BRCA1/2 Pathogenic Variant Carriers: Review of Our Current Understanding and Next Steps

PURPOSE To review the literature exploring endometrial cancer (EC) risk among surgical candidates with germline BRCA1/2 pathogenic variants (PVs) to guide decisions around risk-reducing (rr) hysterectomy in this population. DESIGN A comprehensive review was conducted of the current literature that influences clinical practice and informs expert consensus. We present our understanding of EC risk among BRCA1/2 PV carriers, the risk-modifying factors specific to this patient population, and the available research technology that may guide clinical practice in the future. Limitations of the existing literature are outlined. RESULTS Patients with BRCA1/2 PVs, those with a personal history of tamoxifen use, those who desire long-term hormone replacement therapy, and/or have an elevated BMI are at higher risk of EC, primarily endometrioid EC and/or uterine papillary serous carcinoma, and may benefit from rr-hysterectomy. Although prescriptive clinical guidelines specific to BRCA1/2 PV carriers could inform decisions around rr-hysterectomy, limitations of the current literature prevent more definitive guidance at this time. A large population-based study of a contemporary cohort of BRCA1/2 PV carriers with lifetime follow-up compared with cancer-gene negative controls would advance this topic and facilitate care decisions. CONCLUSION This review validates a potential role for rr-hysterectomy to address EC risk among surgical candidates with BRCA1/2 PVs. Evidence-based clinical guidelines for rr-hysterectomy in BRCA1/2 PV carriers are essential to ensure equitable access to this preventive measure, supporting insurance coverage for patients with either BRCA1 or BRCA2 PVs to pursue rr-hysterectomy. Overall, this review highlights the complexity of EC risk in BRCA1/2 PV carriers and offers a comprehensive framework to shared decision making to inform rr-hysterectomy for BRCA1/2 PV carriers.

Molecular Landscape of Endometrial Stromal Tumors

PURPOSE The molecular heterogeneity of endometrial stromal tumors (ESTs) is demonstrated by the presence of the same fusion gene in distinct pathologic entities, such as endometrial nodules and low-grade endometrial stromal sarcoma, both exhibiting the JAZ1::SUZ12 chimeric transcript. Given the limited knowledge on these tumors, which is based on a small number of cases studied with a restricted range of techniques, we analyzed 47 ESTs to explore their methylation and transcriptomic landscapes. MATERIALS AND METHODS Tumor methylation and transcriptomes profiles were investigated. RESULTS The methylation profile showed distinct clusters, which correlated with established histopathologic and molecular subtypes. The highest methylation value was reported for nuclear factor of activated T cytoplasmic 1, and the lowest was detected for miR34C. Two different 5'—C—phosphate—G—3' (CpG) sites of LMX1B ( LMX1B-cg04996334 and LMX1B ), along with miR34C , showed the same methylation pattern in both low-grade and high-grade endometrial stromal sarcoma (HG-ESS). Similarly, CFAP45 , HDAC4 , ACY3 , MOB3A , and XXYLT1 showed identical methylation patterns in HG-ESS and undifferentiated uterine sarcomas, highlighting the similarities between these tumors within the EST spectrum. We identified 13 novel fusion transcripts involving several genes that are active in transcriptional regulation. CONCLUSION In ESTs, the genes involved in chromosomal rearrangements function as transcription regulators, either directly through the formation of zinc finger motifs or indirectly through epigenetic regulation. The methylation signature is different for distinct subgroups of the EST spectrum, with more aggressive tumors, HG-ESS, and undifferentiated uterine sarcoma, clustering together. Some genes showed similar methylation levels in different entities, highlighting the presence of a continuum in the tumor profile. Methylation levels of CpG sites at specific gene loci may serve as valuable biomarkers for these tumors.

Training, Validating, and Testing Machine Learning Prediction Models for Endometrial Cancer Recurrence

PURPOSE Endometrial cancer (EC) is the most common gynecologic cancer in the United States with rising incidence and mortality. Despite optimal treatment, 15%-20% of all patients will recur. To better select patients for adjuvant therapy, it is important to accurately predict patients at risk for recurrence. Our objective was to train, validate, and test models of EC recurrence using lasso regression and other machine learning (ML) and deep learning (DL) analytics in a large, comprehensive data set. METHODS Data from patients with EC were downloaded from the Oncology Research Information Exchange Network database and stratified into low risk, The International Federation of Gynecology and Obstetrics (FIGO) grade 1 and 2, stage I (N = 329); high risk, or FIGO grade 3 or stages II, III, IV (N = 324); and nonendometrioid histology (N = 239) groups. Clinical, pathologic, genomic, and genetic data were used for the analysis. Genomic data included microRNA, long noncoding RNA, isoforms, and pseudogene expressions. Genetic variation included single-nucleotide variation (SNV) and copy-number variation (CNV). In the discovery phase, we selected variables informative for recurrence ( P < .05), using univariate analyses of variance. Then, we trained, validated, and tested multivariate models using selected variables and lasso regression, MATLAB (ML), and TensorFlow (DL). RESULTS Recurrence clinic models for low-risk, high-risk, and high-risk nonendometrioid histology had AUCs of 56%, 70%, and 65%, respectively. For training, we selected models with AUC >80%: five for the low-risk group, 20 models for the high-risk group, and 20 for the nonendometrioid group. The two best low-risk models included clinical data and CNVs. For the high-risk group, three of the five best-performing models included pseudogene expression. For the nonendometrioid group, pseudogene expression and SNV were overrepresented in the best models. CONCLUSION Prediction models of EC recurrence built with ML and DL analytics had better performance than models with clinical and pathologic data alone. Prospective validation is required to determine clinical utility.

Isolated MLH1 Loss by Immunohistochemistry Because of Benign Germline MLH1 Polymorphisms

PURPOSE Mismatch repair (MMR) immunohistochemistry (IHC) is frequently used to inform prognosis, select (immuno-)therapy, and identify patients for heritable cancer syndrome testing. However, false-negative and false-positive MMR IHC interpretations have been described. MATERIALS AND METHODS Following identification of discordant MMR IHC and DNA-based microsatellite instability testing in a patient with colorectal carcinoma, we retrospectively reviewed institutional archives to identify patient samples with similar discrepancies. RESULTS We report a patient with metastatic colorectal carcinoma who initially received immunotherapy on the basis of apparent isolated loss of MLH1 by IHC; notably, MLH1 promoter hypermethylation was negative. Subsequent evaluation of neoplastic tissue on a DNA-based targeted next-generation sequencing panel demonstrated microsatellite stability, low tumor mutational burden, and a benign MLH1 variant, MLH1 p.V384D, accompanied by loss of heterozygosity. The constellation of findings and repeat MLH1 IHC demonstrating retained expression using a different antibody-clone, supported reclassification of the neoplasm as MMR-proficient. Immunotherapy was discontinued, and cytotoxic chemotherapy was initiated. This index case of apparent discordance between MMR IHC and DNA-based microsatellite instability prompted a retrospective review of institutional archives to identify patient samples with similar discrepancies. Further evaluation of neoplasms harboring MLH1 p.V384D with loss of heterozygosity revealed systematic antibody-dependent interference. The review also identified a second IHC-interference candidate, MLH1 p.A441T. CONCLUSION This study confirms that rare germline polymorphisms can result in incorrect IHC results, potentially affecting selection of optimal therapy and the decision to pursue germline testing. This case further highlights the need for expert molecular pathologic review and communication between clinical and molecular oncology teams.

Up-Front Multigene Panel Testing for Cancer Susceptibility in Patients With Newly Diagnosed Endometrial Cancer: A Multicenter Prospective Study

PURPOSE Clinical utility of up-front multigene panel testing (MGPT) is directly related to the frequency of pathogenic variants (PVs) in the population screened and how genetic findings can be used to guide treatment decision making and cancer prevention efforts. The benefit of MGPT for many common malignancies remains to be determined. In this study, we evaluated up-front MGPT in unselected patients with endometrial cancer (EC) to determine the frequency of PVs in cancer susceptibility genes. METHODS Patients with EC were prospectively enrolled at nine Ohio institutions from October 1, 2017, to December 31, 2020. Nine hundred and sixty-one patients with newly diagnosed EC underwent clinical germline MGPT for 47 cancer susceptibility genes. In addition to estimating the prevalence of germline PVs, the number of individuals identified with Lynch syndrome (LS) was compared between MGPT and tumor-based screening. RESULTS Likely pathogenic variants or PVs were identified in 97 of 961 women (10.1%). LS was diagnosed in 29 of 961 patients (3%; 95% CI, 2.1 to 4.3), with PVs in PMS2 most frequent. MGPT revealed nine patients with LS in addition to the 20 identified through routine tumor-based screening. BRCA1 and BRCA2 PVs were found in 1% (10 of 961; 95% CI, 0.6 to 1.9) of patients and that group was significantly enriched for type II ECs. CONCLUSION This prospective, multicenter study revealed potentially actionable germline variants in 10% of unselected women with newly diagnosed EC, supporting the use of up-front MGPT for all EC patients. The discovery that BRCA1 or BRCA2 heterozygotes frequently had type II cancers points to therapeutic opportunities for women with aggressive histologic EC subtypes.

Phase IIa Study of PLX2853 in Gynecologic Cancers With Known ARID1A Mutation and Phase Ib/IIa Study of PLX2853/Carboplatin in Platinum-Resistant Epithelial Ovarian Cancer

PURPOSE The Bromodomain and Extra-Terminal (BET) domain proteins facilitate the development of many human cancers via epigenetic regulation. BET inhibitors may be effective in reversing platinum resistance in ovarian cancer (OC) and may generate synthetic lethality with ARID1A loss. PLX2853 is an orally active, small-molecule inhibitor of BET bromodomain-mediated interactions that exhibits low nanomolar potency in blocking all four BET family members. METHODS We conducted a multicenter and open-label study with two parallel arms: a phase IIa study of PLX2853 monotherapy in patients with advanced gynecologic malignancies with an ARID1A mutation and a phase Ib/IIa combination study of PLX2853 plus carboplatin in women with platinum-resistant OC. The primary objectives were safety and tolerability for phase Ib and efficacy for both phase IIa portions. Thirty-four of 37 enrolled patients completed at least one post-baseline response assessment. RESULTS Of the 14 evaluable patients on the monotherapy arm, 1 (7.1%) achieved a best overall response of partial response (PR), 5 (35.7%) had stable disease (SD), and 8 (57.1%) had progressive disease (PD). Of the 20 evaluable patients on the combination arm, 1 (5.0%) had PR, 9 (45.0%) had SD, and 10 (50%) had PD. CONCLUSION This study confirmed the safety profile of PLX2853 and demonstrated the feasibility of combination with carboplatin. Although these results did not meet the prespecified response criteria, evidence of clinical activity highlights the rationale for further exploration of BET inhibitors in patients with ARID1A-mutated gynecologic malignancies, possibly in combination with agents targeting potential feedback mechanisms such as the PI3K pathway.

Retrospective Analysis of BRCA -Altered Uterine Sarcoma Treated With Poly(ADP-ribose) Polymerase Inhibitors

PURPOSE Uterine sarcomas are rare, aggressive tumors with limited chemotherapy responsiveness. Poly(ADP-ribose) polymerase inhibitors (PARPis) have emerged as targeted therapies for patients with BRCA mutations across multiple cancer types, with anecdotal responses in uterine sarcoma. This retrospective, single-center study aims to describe relevant genomic and clinical features of patients with BRCA -altered uterine sarcoma and the efficacy of PARPis in this population. METHODS Eligible patients included all histopathologically confirmed uterine sarcoma with pathogenic BRCA alterations identified through Memorial Sloan Kettering Cancer Center-integrated mutation profiling of actionable cancer targets, excluding carcinosarcoma. Genomic, pathologic, and treatment information was extracted from the cBioPortal database and chart review. RESULTS Thirty-five patients were identified with uterine sarcoma harboring pathogenic BRCA alterations, including 33 BRCA2 alterations (70% homozygous deletions, 3% structural variants, 27% mutations) and two BRCA1 mutations. Leiomyosarcoma (LMS) was the most common histology (86%). Thirteen patients with uterine LMS were treated with PARPis in the recurrent/metastatic therapy setting (54% combination therapy regimens) with an overall response rate (ORR) of 46% (1 of 6 for PARPi monotherapy, 5 of 7 for PARPi combination regimens), a clinical benefit rate (CBR) of 62%, and a median progression-free survival (PFS) of 13.2 months (range, 1.0-71.9). The median PFS ratio compared with previous systemic therapy was 1.9 (range, 0.4-53.9), and 58% had a PFS ratio of ≥1.3. The median time on PARPi was 14.5 months (range, 1.3-71.9). The ORR for patients with somatic BRCA2 deletions was 60% (n = 6 of 10), with a CBR of 80% (n = 8 of 10). One patient with metastatic disease and progression on previous hormonal and chemotherapy demonstrated a complete response to PARP/PD-L1 inhibitor combination therapy, ongoing for 70+ months. CONCLUSION PARPis demonstrate promising efficacy in patients with uterine LMS with somatic BRCA2 deletions.

Implications of Multigene Panel Testing on Psychosocial Outcomes: A Comparison of Patients With Pancreatic and Breast or Ovarian Cancer

PURPOSE National Comprehensive Cancer Network guidelines for germline genetic testing have included pancreatic cancer in the context of additional family cancer history for many years but this was not recommended for patients with pancreatic ductal adenocarcinoma (PDAC) independent of a family history until 2019. This hypothesis-generating study reports the results from multigene panel testing for PDAC patients at an academic medical center. PATIENTS AND METHODS This prospective longitudinal feasibility study examined responses to genetic counseling and multigene panel testing among PDAC and breast or ovarian cancer (BrOv) patients between October 2016 and November 2017. Pre- and post-test surveys assessed perceptions of genetic risk and testing, recall, comprehension, and emotional reactions to results using open-ended and closed-ended items. RESULTS Forty-six BrOv and 33 PDAC patients were enrolled, and 44 BrOv and 31 PDAC participants underwent genetic testing. Seven pathogenic variants were identified in six BrOv participants (13.6%), and three pathogenic variants were identified in three PDAC participants (9.7%). The majority of both cohorts expressed similar attitudes about the importance of genetic testing for their personal and family medical management and expressed accurate understanding of implications of their results. Although sample size was small, there were no significant differences between the BrOv and PDAC cohorts for positive or negative emotions. CONCLUSION This study points to high rates of positive emotions and low rates of negative emotions following genetic test results, suggesting that the emotional reactions to genetic test results are similar for patients with BrOv and PDAC, despite poor prognosis with PDAC diagnoses. Because of the unique needs of the PDAC population following diagnosis, a multidisciplinary approach to germline genetic testing following diagnosis may result in best patient and family member outcomes.

State of the Biomarker Science in Ovarian Cancer: A National Cancer Institute Clinical Trials Planning Meeting Report

PURPOSE Despite therapeutic advances in the treatment of ovarian cancer (OC), 5-year survival remains low, and patients eventually die from recurrent, chemotherapy-resistant disease. The National Cancer Gynecologic Cancer Steering Committee identified the integration of scientifically defined subgroups as a top strategic priority in clinical trial planning. METHODS A group of experts was convened to review the scientific literature in OC to identify validated predictive biomarkers that could inform patient selection and treatment stratification. Here, we report on these findings and their potential for use in future clinical trial design on the basis of hierarchal evidence grading. RESULTS The biomarkers were classified on the basis of mechanistic targeting, including DNA repair and replication stress, immunotherapy and tumor microenvironment, oncogenic signaling, and angiogenesis. Currently, BRCA mutations and homologous recombination deficiency to predict poly (ADP-ribose) polymerase inhibitor response are supported in OC by the highest level of evidence. Additional biomarkers of response to agents targeting the pathways above have been identified but require prospective validation. CONCLUSION Although a number of biomarkers of response to various agents in OC have been described in the literature, high-level evidence for the majority is lacking. This report highlights the unmet need for identification and validation of predictive biomarkers to guide therapy and future trial design in OC.

BRCA1/2Variants Identified Through Tumor Genomic Profiling: Assessing Genetic Counseling Outcomes

PURPOSEAs tumor genomic profiling (TGP) is increasingly used to help guide cancer treatment, BRCA variants, which may or may not be reflective of the germline genome, are being identified. As TGP use increases, it is becoming an important tool for referral to genetic counseling and identifying patients with hereditary cancer syndromes such as hereditary breast and ovarian cancer. This study explores genetic counseling referral patterns and germline implications of patients found to have pathogenic BRCA1/2 variants identified through TGP.METHODSParticipants include patients at Huntsman Cancer Institute undergoing TGP through a single commercial laboratory between March 2014 and July 2018. A retrospective chart review was conducted for 62 patients found to have pathogenic variants (PVs) in BRCA1/2 on TGP. Data on genetic counseling referrals and uptake, germline test results, family history, and patient demographics were collected.RESULTSIn the study time frame, 1,899 patients underwent TGP. Testing identified 67 PVs in BRCA1 (23 variants) or BRCA2 (44 variants) in 62 patients. Thirty-five patients first received a referral to a genetic counselor following TGP with 33 patients completing genetic counseling. Of the 30 patients who pursued germline genetic testing following TGP, 11 were discovered to have a previously unknown germline BRCA PV. Nine of these patients were the first in their family diagnosed with hereditary breast and ovarian cancer.CONCLUSIONThis study represents one institution's experience with genetic counseling referrals, uptake, and germline results following TGP. For some patients, TGP will be the first indicator of an underlying hereditary condition. Identifying patients with PVs (which may be germline) through TGP is an important new genetic counseling referral tool that can have important implications for the patient and their family.

Genomic Landscape of Advanced Solid Tumors in Circulating Tumor DNA and Correlation With Tissue Sequencing: A Single Institution's Experience

PURPOSECirculating tumor DNA (ctDNA) has emerged as a promising noninvasive biomarker for baseline characterization and longitudinal monitoring of a tumor throughout disease management. The aim of this study was to evaluate the utility of ctDNA across a wide spectrum of tumor types.METHODSWe retrospectively identified 1,763 patients with advanced cancers who had next-generation sequencing of ctDNA or tumor tissue completed by a designated commercial assay at Northwestern University.RESULTSctDNA identified at least one gene alteration in 90% of patients. The number of detected alterations (NDA) and mutant allele frequency (MAF) of the most frequently mutated genes varied significantly across tumor types, with the highest MAF observed in gastric, colorectal, and breast cancers and the highest NDA observed in colorectal, lung squamous, and ovarian/endometrial cancers. TP53 was the most mutated gene in all tumor types. PIK3CA, ERBB2, BRCA1, and FGFR1 alterations were associated with breast cancer, and ESR1 mutations were exclusively detected in this tumor type. Colorectal cancer was characterized by alterations in KRAS and APC mutations, whereas KRAS, EGFR, PIK3CA, and BRAF mutations were common in lung adenocarcinoma. Concordance between blood and tissue sequencing was notably observed for truncal gene alterations (eg, APC and KRAS), whereas low concordance was often observed in genes associated with treatment resistance mechanisms (eg, RB1 and NF1). Tumor mutational burden (TMB) varied significantly across tumor types, and patients with high MAF or NDA had a significantly higher TMB score with one of the investigated platforms.CONCLUSIONThe study provided new insights into the ctDNA mutational landscape across solid tumors, suggesting new hypotheses-generating data and caveats for future histotype-agnostic workflows integrated with tissue-based biomarkers such as TMB.

PTEN Loss and BRCA1 Promoter Hypermethylation Negatively Predict for Immunogenicity in BRCA-Deficient Ovarian Cancer

PURPOSE Ovarian cancers can exhibit a prominent immune infiltrate, but clinical trials have not demonstrated substantive response rates to immune checkpoint blockade monotherapy. We aimed to understand genomic features associated with immunogenicity in BRCA1/2 mutation–associated cancers. MATERIALS AND METHODS Using the Cancer Genome Atlas whole-exome sequencing, methylation, and expression data, we analyzed 66 ovarian cancers with either germline or somatic loss of BRCA1/2 and whole-exome sequencing, immunohistochemistry, and CyTOF in 20 ovarian cancers with germline BRCA1/2 pathogenic variants from Penn. RESULTS We found two groups of BRCA1/2 ovarian cancers differing in their immunogenicity: (1) 37 tumors significantly enriched for PTEN loss (11, 30%) and BRCA1 promoter–hypermethylated (10, 27%; P = .0016) and (2) PTEN wild-type (28 of 29 tumors) cancers, with the latter group having longer overall survival (OS; P = .0186, median OS not reached v median OS = 66.1 months). BRCA1/2-mutant PTEN loss and BRCA1 promoter–hypermethylated cancers were characterized by the decreased composition of lymphocytes estimated by gene expression ( P = .0030), cytolytic index ( P = .034), and cytokine expression but higher homologous recombination deficiency scores ( P = .00013). Large-scale state transitions were the primary discriminating feature ( P = .001); neither mutational burden nor neoantigen burden could explain differences in immunogenicity. In Penn tumors, PTEN loss and high homologous recombination deficiency cancers exhibited fewer CD3+ ( P = .05), CD8+ ( P = .012), and FOXP3+ ( P = .0087) T cells; decreased PRF1 expression ( P = .041); and lower immune costimulatory and inhibitory molecule expression. CONCLUSION Our study suggests that within ovarian cancers with genetic loss of BRCA1/2 are two subsets exhibiting differential immunogenicity, with lower levels associated with PTEN loss and BRCA hypermethylation. These genomic features of BRCA1/2-associated ovarian cancers may inform considerations around how to optimally deploy immune checkpoint inhibitors in the clinic.

Pertuzumab Plus Trastuzumab in Patients With Endometrial Cancer With ERBB2/3 Amplification, Overexpression, or Mutation: Results From the TAPUR Study

PURPOSE The TAPUR Study is a pragmatic basket trial evaluating antitumor activity of commercially available targeted agents in patients with advanced cancers harboring potentially actionable genomic alterations. Data from a cohort of patients with endometrial cancer (EC) with ERBB2 or ERBB3 (ERBB2/3) amplification, overexpression, or mutation treated with pertuzumab plus trastuzumab (P + T) are reported. METHODS Eligible patients had advanced EC, no standard treatment options, measurable disease (RECIST v1.1), Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, and tumors with ERBB2/3 amplification, overexpression, or mutation. Simon's two-stage design was used with a primary end point of disease control (DC), defined as objective response (OR) or stable disease (SD) of at least 16 weeks (SD16+) duration. Secondary end points include safety, duration of response, duration of SD, progression-free survival (PFS), and overall survival (OS). RESULTS Twenty-eight patients were enrolled from March 2017 to November 2019; all patients were evaluable for efficacy and toxicity. Seventeen patients had tumors with ERBB2/3 amplification and/or overexpression, eight with both ERBB2 amplification and ERBB2/3 mutations, and three with only ERBB2 mutations. Ten patients had DC (two partial response and eight SD16+); all 10 had ERBB2 amplification, and 6 of the 10 patients with DC had >1 ERBB2/3 alteration. DC and OR rates were 37% (95% CI, 21 to 50) and 7% (95% CI, 1 to 24), respectively; the median PFS and median OS were 16 weeks (95% CI, 10-28) and 61 weeks (95% CI, 24-105), respectively. One patient experienced a grade 3 serious adverse event (muscle weakness) at least possibly related to P + T. CONCLUSION P + T has antitumor activity in heavily pretreated patients with EC with ERBB2 amplification and warrants additional study.

Early Clinical and Molecular Biomarkers in Patients With Advanced Ovarian Cancer Undergoing Neoadjuvant Chemotherapy: CHIVA Phase II GINECO Trial

PURPOSE Platinum-based chemotherapy and surgery are pivotal in managing ovarian cancer (OC), yet prognosis remains poor, and early biomarkers for platinum resistance are needed. The neoadjuvant setting provides an opportunity to evaluate tumor responsiveness to platinum chemotherapy in vivo. This study evaluated whether early measures of platinum response combined with molecular alterations could predict surgical outcomes and survival in patients with OC treated with neoadjuvant chemotherapy (NACT). METHODS The CHIVA study enrolled stage III/IV OC patients eligible for three cycles NACT with or without nintedanib, followed by interval debulking surgery. Archival samples underwent extensive sequencing to detect clinically relevant variants and copy number alterations and calculate genomic instability (GIS). Early chemotherapy response measures—cancer antigen 125 kinetics by KELIM, major pathologic response, GIS status, tumor infiltrating lymphocytes (TILs) abundance, and genomic alterations—were correlated with surgery completeness and survival. RESULTS Among 127 patients, the overall response rate was 44%, and the complete cytoreduction (CC0) rate was 54.8%. Homologous recombination deficiency (HRD) was identified in 56% of patients and was associated with better survival. The median progression-free survival was 21.4, 20.5, and 14.4 months in the BRCAmut , BRCAwt /GIS-high, and BRCAwt /GIS-low subgroups, respectively ( P = .001). Unfavorable KELIM predicted lower objective response rate, CC0, and shorter survival, while low intraepithelial TILs (ieTILs) correlated with poor outcomes. Multivariate analysis confirmed KELIM, HRD status, and ieTILs as independent biomarkers. CCNE1 amplifications, observed in 20% of patients, were associated with moderate chemotherapy sensitivity. CONCLUSION HRD status, KELIM, and TILs are key independent biomarkers in advanced OC. CCNE1 amplifications, although typically associated with platinum resistance, were linked to moderate chemotherapy sensitivity, defining an intermediate prognostic subgroup.

Therapeutic Outcomes and Biomarker Potential of CDKL3 of Neoadjuvant Chemotherapy in Patients With Stage IIIC Versus Stage IV Epithelial Ovarian Cancer

PURPOSE Epithelial ovarian cancer (EOC) remains one of the most lethal gynecological malignancies. Although treatment options for newly diagnosed advanced EOC include primary debulking surgery (PDS) or neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS), the comparative effectiveness of these strategies remains uncertain across different disease stages. MATERIALS AND METHODS We conducted a retrospective analysis of 297 patients with EOC whose initial treatment strategy was guided by predicted primary resectability using the Suidan model. We assessed their progression-free survival (PFS) and overall survival outcomes stratified by FIGO stage and treatment approach (PDS v NACT-IDS). We also explored molecular markers associated with prognosis and chemotherapy response. RESULTS Our analysis revealed that patients with stage IIIC EOC had improved survival outcomes with PDS, whereas those with stage IV disease benefited more from NACT-IDS. Furthermore, CDKL3 was identified as a gene associated with poor prognosis and platinum resistance, potentially contributing to the observed differential survival patterns across stages. CONCLUSION These findings suggest that FIGO stage provides additional value in guiding the selection of patients with EOC who may benefit from neoadjuvant chemotherapy. CDKL3 may serve as a promising biomarker for treatment stratification and a therapeutic target to overcome chemoresistance.

Prognostic Significance of Germline DICER1 Pathogenic or Likely Pathogenic Variants in Outcomes of Ovarian Sertoli-Leydig Cell Tumor

PURPOSE Sertoli-Leydig cell tumors (SLCTs) are rare sex cord-stromal tumors, representing <0.5% of all ovarian tumors. We analyze the role of germline DICER1 status in outcomes of ovarian SLCT. METHODS Patients with SLCT were enrolled in the International Pleuropulmonary Blastoma/ DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Medical records were systematically abstracted, and those with known germline DICER1 status were selected for analysis. RESULTS Of 162 patients with SLCT, 60% had a germline DICER1 pathogenic or likely pathogenic (P/LP) variant. The adjusted 3-year recurrence-free survival (RFS) was 87.2% (95% CI, 79.4 to 95.8) for patients with a germline DICER1 P/LP variant compared with 78.1% (95% CI, 66.4 to 91.9) for those without a germline DICER1 P/LP variant ( P = .043). The adjusted 3-year and 5-year overall survival (OS) was 93.9% (95% CI, 87.3 to 100.0) for those with a germline DICER1 P/LP variant compared with the 3-year OS of 91.3% (95% CI, 83.4 to 100.0) and the 5-year OS of 78.2% (95% CI, 63.8 to 95.9) for those without a germline DICER1 P/LP variant ( P = .021). Among patients with a germline DICER1 P/LP variant, the risk of a subsequent, nonrecurrent event was 36.2% (95% CI, 21.4 to 48.1) within 10 years. Previous/concurrent and subsequent neoplasms were rare among those without a germline DICER1 P/LP variant. CONCLUSION This cohort study of patients with SLCT demonstrated that those with germline DICER1 P/LP variants had superior RFS and OS even when adjusting for other prognostic factors. Beyond prognostic implications of a germline DICER1 P/LP variant, germline testing helps identify patients at risk of subsequent neoplasms, including metachronous SLCT.

Optimizing Mainstreaming of Genetic Testing in Parallel With Ovarian and Endometrial Cancer Tumor Testing: How Do We Maximize Our Impact?

PURPOSE Although germline genetic testing (GT) is recommended for all patients with ovarian cancer (OC) and some patients with endometrial cancer (EC), uptake remains low with multiple barriers. Our center performs GT in parallel with somatic testing via a targeted sequencing assay (MSK-IMPACT) and initiates testing in oncology clinics (mainstreaming). We sought to optimize our GT processes for OC/EC. METHODS We performed a quality improvement study to evaluate our GT processes within gynecologic surgery/medical oncology clinics. All eligible patients with newly diagnosed OC/EC were identified for GT and tracked in a REDCap database. Clinical data and GT rates were collected by the study team, who reviewed data for qualitative themes. RESULTS From February 2023 to April 2023, we identified 116 patients with newly diagnosed OC (n = 57) and EC (n = 59). Patients were mostly White (62%); English was the preferred language for 90%. GT was performed in 52 (91%) patients with OC (seven external, 45 MSK-IMPACT) and in 44 (75%) patients with EC (three external, 41 MSK-IMPACT). GT results were available within 3 months for 100% and 95% of patients with OC and EC, respectively. Reasons for not undergoing GT included being missed by the clinical team where there was no record that GT was recommended, feeling overwhelmed, financial and privacy concerns, and language barriers. In qualitative review, we found that resources were concentrated in the initial visit with little follow-up to encourage GT at subsequent points of care. CONCLUSION A mainstreaming approach that couples somatic and germline GT resulted in high testing rates in OC/EC; however, barriers were identified. Processes that encourage GT at multiple care points and allow self-directed, multilingual digital consenting should be piloted.

Genetic Testing Utilization: Discrepancies Between Somatic and Germline Results in Patients With Cancer Reviewed at the UW Health Precision Medicine Molecular Tumor Board

PURPOSE Somatic and germline testing are increasingly used to estimate risks for patients with cancer. Although both germline testing and somatic testing can identify genetic variants that could change a patient's care and eligible treatments, the aims of these tests and their technologies are fundamentally different and cannot be used interchangeably. This study examines the timing and results of somatic and germline genetic testing for patients with cancer at UW Health. METHODS Eight hundred and seventy-seven participants underwent somatic genetic testing, which was reviewed by the Precision Medicine Molecular Tumor Board (PMMTB). Patients were diagnosed with cancers, including breast, colorectal, endometrial, pancreatic, or ovarian cancer, and met National Comprehensive Cancer Network criteria for germline genetic testing. Germline testing details were collected by medical record review. RESULTS The results of this study found that only 310 patients (35%) had germline evaluation before PMMTB review. The percent of germline pathogenic/likely pathogenic variants identified in actionable genes was 28%. Most germline variants were identified in the BRCA1 (26%) and BRCA2 (28%) genes. In total, 65% (54/83) of germline variants were detected with both germline testing and somatic testing; however, 35% (29/83) of germline variants were not identified on somatic results. These results demonstrate the importance of combination germline and somatic testing. CONCLUSION This study highlights the differences in genetic testing types and demonstrates that conducting germline testing at earlier stages of diagnoses is necessary to identify potentially actionable and treatment-specific variants in patients with cancer.

Cancer Risks Associated With TP53 Pathogenic Variants: Maximum Likelihood Analysis of Extended Pedigrees for Diagnosis of First Cancers Beyond the Li-Fraumeni Syndrome Spectrum

PURPOSE Establishing accurate age-related penetrance figures for the broad range of cancer types that occur in individuals harboring a pathogenic germline variant in the TP53 gene is essential to determine the most effective clinical management strategies. These figures also permit optimal use of cosegregation data for classification of TP53 variants of unknown significance. Penetrance estimation can easily be affected by bias from ascertainment criteria, an issue not commonly addressed by previous studies. MATERIALS AND METHODS We performed a maximum likelihood penetrance estimation using full pedigree data from a multicenter study of 146 TP53-positive families, incorporating adjustment for the effect of ascertainment and population-specific background cancer risks. The analysis included pedigrees from Australia, Spain, and United States, with phenotypic information for 4,028 individuals. RESULTS Core Li-Fraumeni syndrome (LFS) cancers (breast cancer, adrenocortical carcinoma, brain cancer, osteosarcoma, and soft tissue sarcoma) had the highest hazard ratios of all cancers analyzed in this study. The analysis also detected a significantly increased lifetime risk for a range of cancers not previously formally associated with TP53 pathogenic variant status, including colorectal, gastric, lung, pancreatic, and ovarian cancers. The cumulative risk of any cancer type by age 50 years was 92.4% (95% CI, 82.2 to 98.3) for females and 59.7% (95% CI, 39.9 to 81.3) for males. Females had a 63.3% (95% CI, 35.6 to 90.1) cumulative risk of developing breast cancer by age 50 years. CONCLUSION The results from maximum likelihood analysis confirm the known high lifetime risk for the core LFS-associated cancer types providing new risk estimates and indicate significantly increased lifetime risks for several additional cancer types. Accurate cancer risk estimates will help refine clinical recommendations for TP53 pathogenic variant carriers and improve TP53 variant classification.

Modifiable Risk Factors and Risk of Colorectal and Endometrial Cancers in Lynch Syndrome: A Systematic Review and Meta-Analysis

PURPOSE Lynch syndrome is the most common hereditary cause of colorectal and endometrial cancers. Modifiable risk factors, including obesity, physical activity, alcohol intake, and smoking, are well-established in sporadic cancers but are less studied in Lynch syndrome. METHODS Searches were conducted on MEDLINE, Embase, and Web of Science for cohort studies that investigated the association between modifiable risk factors and the risk of colorectal or endometrial cancer in people with Lynch syndrome. Adjusted hazard ratios (HRs) and 95% CIs for colorectal and endometrial cancers were pooled using a random effects model. The protocol was prospectively registered on PROSPERO (CRD 42022378462), and the meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology reporting guidelines. RESULTS A total of 770 citations were reviewed. Eighteen studies were identified for qualitative synthesis, with seven colorectal cancer (CRC) studies eligible for meta-analysis. Obesity (HR, 2.38 [95% CI, 1.52 to 3.73]) was associated with increased CRC risk. There was no increased CRC risk associated with smoking (HR, 1.04 [95% CI, 0.82 to 1.32]) or alcohol intake (HR, 1.32 [95% CI, 0.97 to 1.81]). Type 2 diabetes mellitus (T2DM) and some dietary factors might increase risk of CRC although more studies are needed. In a qualitative synthesis of three endometrial cancer cohort studies, female hormonal risk factors and T2DM may affect the risk of endometrial cancer, but obesity was not associated with an increased risk. CONCLUSION Lifestyle recommendations related to weight and physical activity may also be relevant to cancer prevention for individuals with Lynch syndrome. Further high-quality prospective cohort studies, in particular, including endometrial cancer as an end point, are needed to inform evidence-based cancer prevention strategies in this high-risk population.

Risk Stratification of Stage I Grade 3 Endometrioid Endometrial Carcinoma in the Era of Molecular Classification

PURPOSE The role of adjuvant therapy in stage I grade 3 endometrioid endometrial carcinoma (EEC) is debatable. We sought to define the agreement between Post Operative Radiation Therapy in Endometrial Carcinoma 1 (PORTEC-1) high-intermediate risk (HIR) and Gynecologic Oncology Group (GOG)-99 HIR criteria, assess their concordance with The Cancer Genome Atlas molecular subtypes, and evaluate oncologic outcomes in this population. METHODS We identified patients with stage I grade 3 EECs who underwent surgical staging at our institution from January 2014 to January 2020. Patients were stratified into PORTEC-1 HIR, GOG-99 HIR, and The Cancer Genome Atlas molecular subtypes. Adjuvant treatment, and progression-free survival (PFS), and overall survival (OS) were analyzed. RESULTS Seventy-five patients were included. The agreement between PORTEC-1 and GOG-99 HIR classification was 68% (95% CI, 56.2 to 78.3), with a kappa of 0.36 ( P = .001). There was no agreement between PORTEC-1 or GOG-99 HIR classification and a dichotomized molecular classification (copy number-high [CN-H] v other subtypes), with a kappa of 0.03 ( P = .39) and −0.03 ( P = .601), respectively. There was no difference in PFS between PORTEC-1 HIR and non-HIR (HR, 10.9; 95% CI, 0.28 to 4.21) or between GOG-99 HIR and non-HIR (HR, 1.22; 95% CI, 0.32 to 4.6) stage I grade 3 EECs. Patients with CN-H compared with non-CN-H EEC had worse PFS (HR, 5.67; 95% CI, 1.73 to 18.63) and OS (HR, 5.05; 95% CI, 1.13 to 22.5). CONCLUSION In surgically staged patients with stage I grade 3 EEC, PORTEC-1 and GOG-99 HIR criteria were not prognostic and did not identify CN-H patients. Patients with CN-H EEC had worse PFS and OS compared with those with other molecular subtypes. The integration of the molecular classification with recognized clinicopathologic factors may identify patients with higher-risk stage I grade 3 EEC who benefit from additional therapy.

Distinct Genomic Landscapes in Early-Onset and Late-Onset Endometrial Cancer

PURPOSEThe spectrum of somatic mutations among women with endometrial cancer (EC) younger than 50 years (early-onset EC) remains unknown. We investigated distinct somatic mutation patterns among early-onset and late-onset (age ≥ 50 years) EC patients.METHODSThis cohort study included individuals age 18+ years diagnosed with pathologically confirmed EC in the American Association of Cancer Research (AACR) Genomics Evidence Neoplasia Information Exchange (GENIE, v9.1) consortium. We explored tumor mutational burden (TMB) and genomic patterns of EC by age at clinical sequencing using multivariable regression models adjusted for race, ethnicity, histology, sequencing assay, sample type, and TMB.RESULTSAmong 2,425 women with EC, 176 (7.3%) had early-onset EC and 1,923 (79.3%) had nonhypermutated (< 17.78 mutations/Mb) tumors. TMB significantly differed across age and histology groups. Among nonhypermutated ECs, early-onset patients had significantly lower odds of presenting with nonsilent FGFR2 and PIK3R1 somatic mutations compared with late-onset EC patients in adjusted models ( FGFR2: odds ratio [OR] = 0.18, 95% CI, 0.04 to 0.76; PIK3R1: OR = 0.54, 95% CI, 0.31 to 0.92). By contrast, early-onset EC patients had increased odds of presenting with nonsilent CTNNB1 and BRCA2 mutations compared with late-onset patients ( CTNNB1: OR = 3.32, 95% CI, 2.14 to 5.16; BRCA2: OR = 4.01, 95% CI, 1.55 to 10.38). Subsequent analyses stratified by race, ethnicity, and tumor histology identified distinct patterns of APC, KMT2D, KMT2C, and KRAS by race, ethnicity, and PTEN and APC patterns by histologic subtypes.CONCLUSIONEarly-onset EC harbors a unique genomic landscape compared with late-onset disease. A distinct molecular phenotype of early-onset EC provides novel insights into a unique etiology and may yield clinical implications for developing targeted treatment modalities for younger patients.

Clinical Implications of Genomic Loss of Heterozygosity in Endometrial Carcinoma

PURPOSE Homologous recombination deficiency, identified by homologous recombination deficiency gene alterations or high percentage of genome-wide loss of heterozygosity (gLOH), is associated with improved prognosis, platinum sensitivity (PS), and poly (ADP-ribose) polymerase inhibitor response in high-grade ovarian cancer. Since the copy number–high (CN-H) endometrial cancer molecular subtype (EC-MS) shares molecular features with high-grade ovarian cancer, our aim was to assign EC-MS on the basis of comprehensive genomic profiling (CGP) results and evaluate the gLOH status with clinical behavior of EC. METHODS Eighty-two epithelial EC tumor tissues were sequenced by hybrid capture–based CGP, and results were used to assign EC-MS (ultramutated, microsatellite instability–high, CN-low; CN-high). Retrospective chart review established clinical characteristics, including PS. Relationships of PS, EC-MS, gene alterations, and gLOH were assessed statistically. RESULTS PS and EC-MS of CN-H showed statistically significant difference in overall survival (OS). Most notably, when the CN-H EC-MS was subcategorized by gLOH status, there was a significant difference in OS with gLOH-H being associated with longer survival. Cox semi-proportional hazard modeling showed that gLOH, stage, and race were significant in modeling OS. CONCLUSION The method of assigning EC-MS by CGP demonstrates similar clinical features to previous reports of EC-MS assigned by other methods. CGP can also assess gLOH status with gLOH-H most commonly seen in CN-H tumors. CN-H, gLOH-H patients showed significantly improved OS (hazard ratio, 0.100 [0.02-0.51 95% CI]). Thus, gLOH status may be a meaningful prognostic biomarker within the CN-H tumors and possibly across EC-MS.

Age-Related Germline Landscape of Endometrial Cancer: Focus on Early-Onset Cases

PURPOSE Early-onset endometrial cancer (eoEC) is increasing, and germline drivers may be enriched in younger patients. We sought to define germline pathogenic variants (gPVs) in those with EC by age. METHODS We identified patients with EC who underwent clinical tumor-normal sequencing from December 2014 to June 2021 and collected clinical variables. Logistic regression models evaluated associations between age at EC diagnosis and presence of gPV, biallelic inactivation, and Lynch Syndrome (LS). Age categories were defined as early-onset (eoEC, EC < 50 years) and late-onset (EC ≥ 70 years) and were compared with those diagnosed ages 50-69 years. RESULTS Among 1,625 patients with EC, the median age at diagnosis was 63 (range, 24-96) years. We observed gPV in 28 (16%) of 170 patients with eoEC, 152 (14%) of 1,066 patients diagnosed age 50-69 years, and 36 (9%) of 389 patients with late-onset EC ( P = .016). LS was enriched in eoEC, with 6.5% of patients diagnosed age <50 years having LS. In multivariable models compared with those with EC diagnosed age 50-69 years, eoEC was more likely to exhibit biallelic inactivation (odds ratio, 3.34 [95% CI, 1.44 to 7.35]) and be associated with LS (hazard ratio [HR], 3.49 [95% CI, 1.63 to 7.01]). Among early-onset EC, 14 (50%) of 28 gPV were high penetrance and 14 (50%) of 28 exhibited biallelic inactivation. However, heterogeneity was observed, and rates of gPV were 8.9% and 19%, biallelic inactivation was 0% and 11%, and LS was 2.2% and 8% in those diagnosed age <40 years and 40-49 years, respectively. CONCLUSION Rates of gPV, biallelic inactivation, and LS differ across age groups for EC, with high-penetrant genes driving tumorigenesis enriched in younger patients. However, very-early-onset EC may have different drivers and necessitates more research.

5-Hydroxymethylated Biomarkers in Cell-Free DNA Predict Occult Colorectal Cancer up to 36 Months Before Diagnosis in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

PURPOSE Using the prostate, lung, colorectal, and ovarian (PLCO) Cancer Screening Trial samples, we identified cell-free DNA (cfDNA) candidate biomarkers bearing the epigenetic mark 5-hydroxymethylcytosine (5hmC) that detected occult colorectal cancer (CRC) up to 36 months before clinical diagnosis. MATERIALS AND METHODS We performed the 5hmC-seal assay and sequencing on ≤8 ng cfDNA extracted from PLCO study participant plasma samples, including n = 201 cases (diagnosed with CRC within 36 months of blood collection) and n = 401 controls (no cancer diagnosis on follow-up). We conducted association studies and machine learning modeling to analyze the genome-wide 5hmC profiles within training and validation groups that were randomly selected at a 2:1 ratio. RESULTS We successfully obtained 5hmC profiles from these decades-old samples. A weighted Cox model of 32 5hmC-modified gene bodies showed a predictive detection value for CRC as early as 36 months before overt tumor diagnosis (training set AUC, 77.1% [95% CI, 72.2 to 81.9] and validation set AUC, 72.8% [95% CI, 65.8 to 79.7]). Notably, the 5hmC-based predictive model showed comparable performance regardless of sex and race/ethnicity, and significantly outperformed risk factors such as age and obesity (assessed as BMI). Finally, when splitting cases at median weighted prediction scores, Kaplan-Meier analyses showed significant risk stratification for CRC occurrence in both the training set (hazard ratio, [HR], 3.3 [95% CI, 2.6 to 5.8]) and validation set (HR, 3.1 [95% CI, 1.8 to 5.8]). CONCLUSION Candidate 5hmC biomarkers and a scoring algorithm have the potential to predict CRC occurrence despite the absence of clinical symptoms and effective predictors. Developing a minimally invasive clinical assay that detects 5hmC-modified biomarkers holds promise for improving early CRC detection and ultimately patient outcomes.

Exome Sequencing Identifies Carriers of the Autosomal Dominant Cancer Predisposition Disorders Beyond Current Practice Guideline Recommendations

PURPOSE The autosomal dominant cancer predisposition disorders hereditary breast and ovarian cancer (HBOC) and Lynch syndrome (LS) are genetic conditions for which early identification and intervention have a positive effect on the individual and public health. The goals of this study were to determine whether germline genetic screening using exome sequencing could be used to efficiently identify carriers of HBOC and LS. METHODS Participants were recruited from three geographically and racially diverse sites in the United States (Rochester, MN; Phoenix, AZ; Jacksonville, FL). Participants underwent Exome+ sequencing (Helix Inc, San Mateo, CA) and return of results for specific genetic findings: HBOC ( BRCA1 and BRCA1) and LS ( MLH1, MSH2, MSH6, PMS2, and EPCAM). Chart review was performed to collect demographics and personal and family cancer history. RESULTS To date, 44,306 participants have enrolled in Tapestry. Annotation and interpretation of all variants in genes for HBOC and LS resulted in the identification of 550 carriers (prevalence, 1.24%), which included 387 with HBOC (27.2% BRCA1, 42.8% BRCA2) and 163 with LS (12.3% MSH6, 8.8% PMS2, 4.5% MLH1, 3.8% MSH2, and 0.2% EPCAM). More than half of these participants (52.1%) were newly diagnosed carriers with HBOC and LS. In all, 39.2% of HBOC/LS carriers did not satisfy National Comprehensive Cancer Network (NCCN) criteria for genetic evaluation. NCCN criteria were less commonly met in underrepresented minority populations versus self-reported White race (51.5% v 37.5%, P = .028). CONCLUSION Our results emphasize the need for wider utilization of germline genetic sequencing for enhanced screening and detection of individuals who have LS and HBOC cancer predisposition syndromes.

Comprehensive Screening for Early Cancer Detection in Individuals With Genetic Predisposition

PURPOSE To evaluate the effectiveness of a comprehensive screening program for individuals with genetic predisposition to cancer, focusing on early detection and improved treatment outcomes through systematic clinical, instrumental, and laboratory monitoring of pathogenic/likely pathogenic (P/LP) variant carriers. MATERIALS AND METHODS The registry screening program included two groups: (1) patients with cancer with confirmed germline P/LP variants associated with cancer predisposition, and (2) healthy individuals carrying germline P/LP variants predisposing to cancer development. In total, 816 participants were included. Participants underwent routine screening, including medical history recording, and instrumental and laboratory investigations accompanied by consultations of different specialists. The study compared the age and stage of the disease at the time of cancer diagnosis between healthy P/LP variant carriers (Group A, n = 554) and patients with cancer (Group B, n = 262). RESULTS Among the 554 healthy P/LP variant carriers in Group A, 57 patients of cancer (10.2%) were identified, predominantly breast and ovarian cancers (Group A1). In Group A1, 96.4% of detected cancers were at stages I to II. The average age at diagnosis in Group A1 was 52 ± 12 years, with 35% of patients detected within 6 months, 58% within 1 year, and 7% within 1.5 years after inclusion of an individual into the screening program. In Group B1 (191 patients with breast cancer), 20.9% were diagnosed at stages III to IV. Notably, 27% of aggressive molecular biological subtypes of breast cancer (Luminal B and triple-negative) were identified at stage I in Group A1, and the most common BRCA1 variant was c.5266dupC (rs80357906), accounting for 64.3% of such patients. CONCLUSION The comprehensive screening program demonstrated the effectiveness of early detection of malignancies in individuals with genetic predisposition to cancer development. The identification of a significant proportion of early-stage cancers, particularly aggressive subtypes, highlights the importance of tailored screening strategies for the cohort of patients at high risk of cancer development.

Microsatellite Instability Is Insufficiently Used as a Biomarker for Lynch Syndrome Testing in Clinical Practice

PURPOSE The pan-cancer presence of microsatellite instability (MSI)–positive tumors demonstrates its clinical utility as an agnostic biomarker for identifying immunotherapy-eligible patients. Additionally, MSI is a hallmark of Lynch syndrome (LS), the most prevalent cancer susceptibility syndrome among patients with colorectal and endometrial cancer. Therefore, MSI-high results should inform germline genetic testing for cancer-predisposing genes. However, in clinical practice, such analysis is frequently disregarded. METHODS A next-generation sequencing (NGS)–based technique was used for MSI analysis in 4,553 patients with various tumor types. Upon request, somatic BRAF gene analysis was conducted. In addition, hereditary testing of cancer-associated genes was performed in MSI-high cases using a capture-based NGS protocol. MLH1 promoter methylation analysis was conducted retrospectively in patients with colorectal and endometrial cancer to further investigate the origin of MSI at the tumor level. RESULTS The MSI positivity rate for the entire cohort was 5.27%. Endometrial, gastric, colorectal, urinary tract, and prostate cancers showed the highest proportion of MSI-high cases (15.69%, 8.54%, 7.40%, 4.55%, and 3.19%, respectively). A minority of 45 patients (22.73%) among the MSI-high cases underwent germline testing to determine whether the mismatch repair pathway deficiency was inherited. 24.44% of those who performed the genetic test carried a pathogenic variant in an LS-associated gene. Three MSI-high individuals had non-LS gene alterations, including BRCA1, BRCA2, and CDKN2A pathogenic variants, indicating the presence of non–LS-associated gene alterations among MSI-high patients. CONCLUSION Although MSI analysis is routinely performed in clinical practice, as many as 77% of MSI-high patients do not undergo LS genetic testing, despite international guidelines strongly recommending it. BRAF and MLH1 methylation analysis could shed light on the somatic origin of MSI in 42.50% of the MSI-high patients; however, MLH1 analysis is barely ever requested in clinical practice.

Biallelic BRCA Loss and Homologous Recombination Deficiency in Nonbreast/Ovarian Tumors in Germline BRCA1/2 Carriers

PURPOSE Breast and ovarian tumors in germline BRCA1/2 carriers undergo allele-specific loss of heterozygosity, resulting in homologous recombination deficiency (HRD) and sensitivity to poly-ADP-ribose polymerase (PARP) inhibitors. This study investigated whether biallelic loss and HRD also occur in primary nonbreast/ovarian tumors that arise in germline BRCA1/2 carriers. METHODS A clinically ascertained cohort of BRCA1/2 carriers with a primary nonbreast/ovarian cancer was identified, including canonical (prostate and pancreatic cancers) and noncanonical (all other) tumor types. Whole-exome sequencing or clinical sequencing results (n = 45) were analyzed. A pan-cancer analysis of nonbreast/ovarian primary tumors from germline BRCA1/2 carriers from The Cancer Genome Atlas (TCGA, n = 73) was used as a validation cohort. RESULTS Ages of nonbreast/ovarian cancer diagnosis in germline BRCA1/2 carriers were similar to controls for the majority of cancer types. Nine of 45 (20%) primary nonbreast/ovarian tumors from germline BRCA1/2 carriers had biallelic loss of BRCA1/2 in the clinical cohort, and 23 of 73 (32%) in the TCGA cohort. In the combined cohort, 35% and 27% of primary canonical and noncanonical BRCA tumor types, respectively, had biallelic loss. High HRD scores (HRDex > 42) were detected in 81% of tumors with biallelic BRCA loss compared with 22% ( P < .001) of tumors without biallelic BRCA loss. No differences in genomic profile, including mutational signatures, mutation spectrum, tumor mutational burden, or microsatellite instability, were found in primary nonbreast/ovarian tumors with or without biallelic BRCA1/2 loss. CONCLUSION A proportion of noncanonical primary tumors have biallelic loss and evidence of HRD. Our data suggest that assessment of biallelic loss and HRD could supplement identification of germline BRCA1/2 mutations in selection of patients for platinum or PARP inhibitor therapy.

Normalized LST Is an Efficient Biomarker for Homologous Recombination Deficiency and Olaparib Response in Ovarian Carcinoma

PURPOSE The efficiency of the Myriad Homologous Recombination Deficiency (HRD) test to guide the use of poly (ADP-ribose) polymerase (PARP) inhibitors has been demonstrated in several phase III trials. However, a need exists for alternative clinically validated tests. METHODS A novel biomarker for HRD was developed using The Cancer Genome Atlas database and, as part of the ENGOT HRD European Initiative, applied to 469 samples from the PAOLA-1/ENGOT-ov25 trial. Results were compared with the Myriad myChoice Genomic Instability Score (GIS) with respect to the progression-free survival in the olaparib + bevacizumab and placebo + bevacizumab arms. RESULTS Analysis of the TCGA cohort revealed that a normalization of the number of large-scale state transitions by the number of whole-genome doubling events allows a better separation and classification of HRD samples than the GIS. Analysis of the PAOLA-1 samples, using the Geneva test (OncoScan + nLST), yielded a lower failure rate (27 of 469 v 59 of 469) and a hazard ratio of 0.40 (95% CI, 0.28 to 0.57) compared with 0.37 for Myriad myChoice (BRCAm or GIS+) in the nLST-positive samples. In patients with BRCAwt, the Geneva test identified a novel subpopulation of patients, with a favorable 1-year PFS (85%) but a poor 2-year PFS (30%) on olaparib + bevacizumab treatment. CONCLUSION The proposed test efficiently separates HRD-positive from HRD-negative patients, predicts response to PARP inhibition, and can be easily deployed in a clinical laboratory for routine practice. The performance is similar to the available commercial test, but its lower failure rate allows an increase in the number of patients who will receive a conclusive laboratory result.

High Concordance of Different Assays in the Determination of Homologous Recombination Deficiency–Associated Genomic Instability in Ovarian Cancer

PURPOSE Poly(ADP-ribose) polymerase inhibitors (PARPi) have shown promising clinical results in the treatment of ovarian cancer. Analysis of biomarker subgroups consistently revealed higher benefits for patients with homologous recombination deficiency (HRD). The test that is most often used for the detection of HRD in clinical studies is the Myriad myChoice assay. However, other assays can also be used to assess biomarkers, which are indicative of HRD, genomic instability (GI), and BRCA1/ 2 mutation status. Many of these assays have high potential to be broadly applied in clinical routine diagnostics in a time-effective decentralized manner. Here, we compare the performance of a multitude of alternative assays in comparison with Myriad myChoice in high-grade serous ovarian cancer (HGSOC). METHODS DNA from HGSOC samples was extracted from formalin-fixed paraffin-embedded tissue blocks of cases previously run with the Myriad myChoice assay, and GI was measured by multiple molecular assays (CytoSNP, AmoyDx, Illumina TSO500 HRD, OncoScan, NOGGO GISv1, QIAseq HRD Panel and whole genome sequencing), applying different bioinformatics algorithms. RESULTS Application of different assays to assess GI, including Myriad myChoice, revealed high concordance of the generated scores ranging from very substantial to nearly perfect fit, depending on the assay and bioinformatics pipelines applied. Interlaboratory comparison of assays also showed high concordance of GI scores. CONCLUSION Assays for GI assessment not only show a high concordance with each other but also in correlation with Myriad myChoice. Thus, almost all of the assays included here can be used effectively to assess HRD-associated GI in the clinical setting. This is important as PARPi treatment on the basis of these tests is compliant with European Medicines Agency approvals, which are methodologically not test-bound.

Mainstreaming Genetic Testing for Epithelial Ovarian Cancer by Oncology Providers: A Survey of Current Practice

PURPOSE With limitations in early detection and poor treatment response, ovarian cancer is associated with significant morbidity and mortality. Up to 25% of epithelial ovarian cancer (EOC) is related to a hereditary predisposition. Current National Comprehensive Cancer Network guidelines recommend that all individuals diagnosed with EOC be offered germline genetic testing. Although this would ideally be performed by genetics professionals, a shortage of genetic counselors can affect timely access to these services. This study sought to investigate the current genetic testing practices of oncology providers to determine the feasibility of oncologist-led genetic testing for patients with EOC. METHODS A survey was distributed to members of the Society of Gynecologic Oncologists with questions regarding timing, frequency, and type of cancer genetic testing, referrals to genetics professionals, confidence with aspects of genetic testing, and any barriers to these processes. RESULTS We received 170 evaluable responses. Eighty-five percent of providers always ordered genetic testing for patients with EOC. Most providers ordered germline multigene panel testing (95.8%), generally at diagnosis (64.5%). Provider confidence with the genetic testing process was generally high and significantly differed by providers' testing practices, namely, respondents who reported always ordering genetic testing tended to be more confident in ordering testing ( P = .008), interpreting results ( P = .005), and counseling a patient ( P = .002). Patient disinterest and concerns for insurance coverage were commonly cited as barriers to testing and referrals. CONCLUSION The findings from this study suggest that oncologist-led genetic testing for patients with EOC, with referrals to genetics professionals when appropriate, has the potential to be a viable alternative service delivery model to increase access to genetic testing for patients diagnosed with EOC.

Spectrum ofBRAFMutations and Gene Rearrangements in Ovarian Serous Carcinoma

PURPOSELow-grade serous carcinoma (LGSC) is a rare type of ovarian cancer, which commonly arises from serous borderline tumor (SBT) and is characterized by frequent activating mutations in the mitogen-activated protein kinase pathway, including BRAF. The BRAFV600Emutation is associated with improved prognosis in SBT and LGSC, and responses to BRAF inhibitor therapy have been reported. We sought to characterize the clinicopathologic and molecular features of BRAF-driven tubo-ovarian and primary peritoneal serous tumors.METHODSRetrospective analysis of our institutional cohort of SBTs (n = 22), LGSCs (n = 119) and high-grade serous carcinomas (HGSCs, n = 1,290) subjected to targeted massively parallel sequencing was performed to identify cases with BRAF genetic alterations. Putative BRAF rearrangements were confirmed using targeted RNA sequencing and/or fluorescence in situ hybridization (FISH). BRAFV600Eoncoprotein expression was assessed by immunohistochemistry on selected cases.RESULTSBRAF somatic genetic alterations were identified in 29 of 1,431 (2%) serous tumors and included mutations (n = 24), gene rearrangements (n = 3), and amplification (n = 2). BRAF mutations were more frequent in SBTs (7 of 22; 32%) compared with LGSCs (11 of 119; 9%, P = .009) and HGSCs (6 of 1,290; 0.5%; P < .0001, SBT/LGSC v HGSC). The BRAFV600Ehotspot mutation was most common (n = 16); however, other BRAF driver mutations were also detected (n = 8). BRAF mutations were often clonal or truncal in SBTs and LGSCs, but subclonal in most HGSCs. Pathogenic BRAF gene fusions were identified in LGSCs (n = 2) and HGSC (n = 1) and involved distinct fusion partners ( AGK, MKRN1, and AGAP3). Three patients with BRAF-mutant LGSC were treated with targeted mitogen-activated protein kinase inhibitors, one of whom was maintained on therapy for over 3 years with clinical benefit.CONCLUSIONRecognition of BRAF alterations beyond V600E mutation in LGSC may have clinical implications for appropriate targeted therapy selection.

Germline Testing and Somatic Tumor Testing forBRCA1/2Pathogenic Variants in Ovarian Cancer: What Is the Optimal Sequence of Testing?

PURPOSEIn 2020, ASCO recommended that all women with epithelial ovarian cancer have germline testing for BRCA1/2 mutations, and those without a germline pathogenic variant (PV) should have somatic tumor testing to determine eligibility for a poly (ADP-ribose) polymerase inhibitor. Consequently, the majority of patients with ovarian cancer will have both germline testing and somatic testing. An alternate strategy is tumor testing first and then germline testing if there is a PV in the tumor and/or significant family history. The objective was to conduct a cost-effectiveness analysis comparing the two testing strategies.METHODSThe Markov model compared the costs (US dollars) and benefits of two testing strategies for newly diagnosed ovarian cancer: (1) ASCO strategy and (2) tumor testing triage for germline testing. Data were applied from SOLO-1, and costs were from wholesale acquisition prices, Medicare, and published sources. Sensitivity analyses accounted for uncertainty around various parameters. Monte Carlo simulation estimated the number tested and identified with germline and somatic BRCA PV for olaparib maintenance treatment annually in the US population.RESULTSThe ASCO strategy was more effective but more costly than tumor testing triage in identifying patients for olaparib, with an incremental cost-effectiveness ratio of $281,296 US dollars per progression-free life year gained. Assuming 10,000 eligible patients with ovarian cancer annually, Monte Carlo simulation yielded comparable numbers of patients with BRCA PV in the germline and tumor with the ASCO and tumor testing triage strategies (2,080 v 2,062, respectively), but substantially higher number of patients tested using the ASCO strategy (8,052 v 3,076).CONCLUSIONThe ASCO strategy may identify more BRCA PVs but is not cost-effective. Tumor testing in epithelial ovarian cancer as triage for germline testing is the favored strategy in this health care system.

Hyperthermic Intraperitoneal Chemotherapy–Induced Molecular Changes in Humans Validate Preclinical Data in Ovarian Cancer

PURPOSE Hyperthermic intraperitoneal chemotherapy (HIPEC) confers a survival benefit in epithelial ovarian cancer (EOC) and in preclinical models. However, the molecular changes induced by HIPEC have not been corroborated in humans. PATIENTS AND METHODS A feasibility trial evaluated clinical and safety outcomes of HIPEC with cisplatin during optimal cytoreductive surgery (CRS) in patients with EOC diagnosed with stage III, IV, or recurrent EOC. Pre- and post-HIPEC biopsies were comprehensively profiled with genomic and transcriptomic sequencing to identify mutational and RNAseq signatures correlating with response; the tumor microenvironment was profiled to identify potential immune biomarkers; and transcriptional signatures of tumors and normal samples before and after HIPEC were compared to investigate HIPEC-induced acute transcriptional changes. RESULTS Thirty-five patients had HIPEC at the time of optimal CRS; all patients had optimal CRS. The median progression-free survival (PFS) was 24.7 months for primary patients and 22.4 for recurrent patients. There were no grade 4 or 5 adverse events. Anemia was the most common grade 3 adverse event (43%). Hierarchical cluster analyses identified distinct transcriptomic signatures of good versus poor responders to HIPEC correlating with a PFS of 29.9 versus 7.3 months, respectively. Among good responders, significant HIPEC-induced molecular changes included immune pathway upregulation and DNA repair pathway downregulation. Within cancer islands, % programmed cell death protein 1 expression in CD8+ T cells significantly increased after HIPEC. An exceptional responder (PFS 58 months) demonstrated the highest programmed cell death protein 1 increase. Heat shock proteins comprised the top differentially upregulated genes in HIPEC-treated tumors. CONCLUSION Distinct transcriptomic signatures identify responders to HIPEC, and preclinical model findings are confirmed for the first time in a human cohort.

Randomized Phase II Study of Gemcitabine With or Without ATR Inhibitor Berzosertib in Platinum-Resistant Ovarian Cancer: Final Overall Survival and Biomarker Analyses

PURPOSE The multicenter, open-label, randomized phase 2 NCI-9944 study ( NCT02595892 ) demonstrated that addition of ATR inhibitor (ATRi) berzosertib to gemcitabine increased progression-free survival (PFS) compared to gemcitabine alone (hazard ratio [HR]=0.57, one-sided log-rank P = .044, which met the one-sided significance level of 0.1 used for sample size calculation). METHODS We report here the final overall survival (OS) analysis and biomarker correlations (ATM expression by immunohistochemistry, mutational signature 3 and a genomic biomarker of replication stress) along with post-hoc exploratory analyses to adjust for crossover from gemcitabine to gemcitabine/berzosertib. RESULTS At the data cutoff of January 27, 2023 (>30 months of additional follow-up from the primary analysis), median OS was 59.4 weeks with gemcitabine/berzosertib versus 43.0 weeks with gemcitabine alone (HR 0.79, 90% CI 0.52 to 1.2, one-sided log-rank P = .18). An OS benefit with addition of berzosertib to gemcitabine was suggested in patients stratified into the platinum-free interval ≤3 months (N = 26) subgroup (HR, 0.48, 90% CI 0.22 to 1.01, one-sided log-rank P =.04) and in patients with ATM-negative/low (N = 24) tumors (HR, 0.50, 90% CI 0.23 to 1.08, one-sided log-rank P = .06). CONCLUSION The results of this follow-up analysis continue to support the promise of combined gemcitabine/ATRi therapy in platinum resistant ovarian cancer, an active area of investigation with several ongoing clinical trials.

Prevalence of BRCA1 Promoter Methylation in Cohorts of Individuals With and Without Cancer Assessed by Circulating Cell-Free DNA

PURPOSE BRCA1 promoter methylation ( BRCA1 meth) affects 20%-27% of triple-negative breast cancer (TNBC) and ovarian cancer (OvCa) and has therapeutic predictive value in both cancer types. BRCA1 meth is established during early embryonic development as a constitutional event, and its detection in the peripheral blood cells of unaffected women associates with increased risk for breast cancer and OvCa. Thus, facile and sensitive assessment of BRCA1 meth is an important component for both risk assessment and the therapeutic management of these cancer types. METHODS We used the GRAIL circulating cell-free DNA (cfDNA)–based targeted methylation platform to quantify BRCA1 meth in cfDNA (cf BRCA1 meth) from plasma samples of individuals with and without cancer. RESULTS Detection of cf BRCA1 meth was accurate and sensitive, with an empirical LoD 95 of 0.0081. cf BRCA1 meth was found in 4.1% (113/2,790) of individuals without cancer, and it was significantly more prevalent in females compared with males (4.8% v 2.9%, P = .016), suggesting that the dynamics of BRCA1 promoter methylation and its consequences for cancer development may differ by sex. In a pan-cancer cohort comprising 2,849 patients and representing 15 tissue types, cf BRCA1 meth was enriched only in TNBC (15.2%, P = .001) and OvCa (13.9%, P = .014). Importantly, in these cf BRCA1 meth-positive cases, the fraction of cf BRCA1 meth was correlated with a methylation-based estimate of tumor burden. CONCLUSION Our findings demonstrate that BRCA1 meth can be robustly detected using cfDNA assessment both as a constitutional event in noncancer samples and as a metric of BRCA1 meth tumor burden in individuals with BRCA1 meth cancers. Therefore, the GRAIL assay provides a single quantitative platform that can be used to explore the role of BRCA1 meth in cancer risk and therapeutic response.

Gemogenovatucel-T Advantage in Clonal Tumor Mutation Burden–High Ovarian Cancer

PURPOSE Frontline ovarian cancer treatment protocols involving bevacizumab, poly (ADP-ribose) polymerase inhibitors, and PD-1/PD-L1 inhibitors have failed to improve overall survival (OS) in patients with homologous recombination–proficient (HRP) tumors. To determine mechanistic mutation signatures associated with OS advantage, we constructed a whole-exome sequencing bioinformatic pipeline assay to analyze all 91 patients enrolled in the double-blind randomized placebo-controlled phase II VITAL trial. METHODS We hypothesized that patients with stage IIIb-IV ovarian cancer who have HRP profile and high clonal tumor mutation burden (cTMB-H) will achieve greater response when undergoing maintenance therapy with gemogenovatucel-T. Our primary objective was assessment of OS using the Kaplan-Meier method among randomly assigned patients receiving either gemogenovatucel-T or placebo. RESULTS The median OS in cTMB-H/HRP patients treated with gemogenovatucel-T was 68 months versus 19 months in those treated with placebo (hazard ratio [HR], 0.23; 95% CI, 0.06 to 0.83; 1-sided P = .008). The cTMB-H patients in the non-HRP group did not demonstrate OS advantage (HR, 0.99; 95% CI, 0.39 to 2.47; 1-sided P = .488). No grade 3 treatment-related toxicity was observed in the gemogenovatucel-T group with a follow-up of 8.4 years. CONCLUSION These results demonstrate OS advantage for maintenance treatment of adult females with newly diagnosed, advanced stage IIIb-IV ovarian cancer with HRP status and cTMB-H profile who are in complete response after debulking surgery and frontline platinum-based doublet chemotherapy.

Publisher

American Society of Clinical Oncology (ASCO)

ISSN

2473-4284