Ying L. Liu

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.

A tale of two pathways: Review of immune checkpoint inhibitors in DNA mismatch repair‐deficient and microsatellite instability‐high endometrial cancers

AbstractThe DNA mismatch repair (MMR) pathway is critical for correcting DNA mismatches generated during DNA replication. MMR‐deficiency (MMR‐D) leads to microsatellite instability (MSI) associated with an increased mutation rate, driving cancer development. This is particularly relevant in endometrial cancer (EC) as 25%–30% of tumors are of MMR‐D/MSI‐high (MSI‐H) phenotype. Comprehensive assessment using immunohistochemistry (IHC) and sequencing‐based techniques are necessary to fully evaluate ECs given the importance of molecular subtyping in staging and prognosis. This also influences treatment selection as clinical trials have demonstrated survival benefits for immune checkpoint inhibitors (ICIs) alone and in combination with chemotherapy for MMR‐D/MSI‐H EC patients in various treatment settings. As a portion of MMR‐D/MSI‐H ECs are driven by Lynch syndrome, an inherited cancer predisposition syndrome that is also associated with colorectal cancer, this molecular subtype also prompts germline assessment that can affect at‐risk family members. Additionally, heterogeneity in the tumor immune microenvironment and tumor mutation burden (TMB) have been described by MMR mechanism, meaning MLH1 promoter hypermethylation versus germline/somatic MMR gene mutation, and this may affect response to ICI therapies. Variations by ancestry in prevalence and mechanism of MMR‐D/MSI‐H tumors have also been reported and may influence health disparities given observed differences in tumors of Black compared to White patients which may affect ICI eligibility. These observations highlight the need for additional prospective studies to evaluate the nuances regarding MMR‐D heterogeneity as well as markers of resistance to inform future trials of combination therapies to further improve outcomes for patients with EC.

Olaparib as treatment for platinum‐sensitive relapsed ovarian cancer by BRCA mutation and homologous recombination deficiency: Phase 2 LIGHT study final overall survival analysis

AbstractBackgroundLIGHT (oLaparib In HRD‐Grouped Tumor types; NCT02983799) prospectively evaluated olaparib treatment in patients with platinum‐sensitive relapsed ovarian cancer (PSROC) assigned to cohorts by known BRCA mutation (BRCAm) and homologous recombination deficiency (HRD) status: germline BRCAm (gBRCAm), somatic BRCAm (sBRCAm), HRD‐positive non‐BRCAm, and HRD‐negative. At the primary analysis, olaparib treatment demonstrated activity across all cohorts, with greatest efficacy in terms of objective response rate and progression‐free survival observed in the g/sBRCAm cohorts. The authors report final overall survival (OS).MethodsIn this phase 2, open‐label, noncomparative study, patients with PSROC and one or more prior line of platinum‐based chemotherapy were assigned to cohorts by BRCAm and HRD status. OS was a secondary end point. Tumors were analyzed using Myriad BRACAnalysis CDx and MyChoice CDx assays; HRD‐positive tumors were defined using a genomic instability score of ≥42.ResultsOf 272 enrolled patients, 271 received olaparib and 270 met the inclusion criteria for the efficacy analysis. At data cutoff, 18‐month OS rates in the gBRCAm, sBRCAm, HRD‐positive non‐BRCAm, and HRD‐negative cohorts were 86.4%, 88.0%, 78.6%, and 59.6%, respectively. No new safety signals were observed. In a post hoc analysis, patients on treatment for >18 months were most frequently present in g/sBRCAm cohorts (31.0%).ConclusionsOlaparib treatment continued to demonstrate benefit across all cohorts. Consistent with the primary analysis, the highest OS rates were observed in the BRCAm cohorts, regardless of g/sBRCAm. In patients without a BRCAm, a higher OS rate was observed in the HRD‐positive non‐BRCAm than the HRD‐negative cohorts. These results highlight the importance of biomarker testing in this treatment setting.

Pathogenic germline variants in patients with endometrial cancer of diverse ancestry

AbstractBackgroundRacial disparities in outcomes exist in endometrial cancer (EC). The contribution of ancestry‐based variations in germline pathogenic variants (gPVs) is unknown.MethodsGermline assessment of ≥76 cancer predisposition genes was performed in patients with EC undergoing tumor‐normal Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets sequencing from January 1, 2015 through June 30, 2021. Self‐reported race/ethnicity and Ashkenazi Jewish ancestry data classified patients into groups. Genetic ancestry was inferred from Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets. Rates of gPV and genetic counseling were compared by ancestry.ResultsAmong 1625 patients with EC, 216 (13%) had gPVs; 15 had >1 gPV. Rates of gPV varied by self‐reported ancestry (Ashkenazi Jewish, 40/202 [20%]; Asian, 15/124 [12%]; Black/African American (AA), 12/171 [7.0%]; Hispanic, 15/124 [12%]; non‐Hispanic (NH) White, 129/927 [14%]; missing, 5/77 [6.5%]; p = .009], with similar findings by genetic ancestry (p < .001). We observed a lower likelihood of gPVs in patients of Black/AA (odds ratio [OR], 0.44; 95% CI, 0.22–0.81) and African (AFR) ancestry (OR, 0.42; 95% CI, 0.18–0.85) and a higher likelihood in patients of Ashkenazi Jewish genetic ancestry (OR, 1.62; 95% CI; 1.11–2.34) compared with patients of non‐Hispanic White/European ancestry, even after adjustment for age and molecular subtype. Somatic landscape influenced gPVs with lower rates of microsatellite instability‐high tumors in patients of Black/AA and AFR ancestry. Among those with newly identified gPVs (n = 114), 102 (89%) were seen for genetic counseling, with lowest rates among Black/AA (75%) and AFR patients (67%).ConclusionsIn those with EC, gPV and genetic counseling varied by ancestry, with lowest rates among Black/AA and AFR patients, potentially contributing to disparities in outcomes given implications for treatment and cancer prevention.Plain Language Summary Black women with endometrial cancer do worse than White women, and there are many reasons for this disparity. Certain genetic changes from birth (mutations) can increase the risk of cancer, and it is unknown if rates of these changes are different between different ancestry groups. Genetic mutations in 1625 diverse women with endometrial cancer were studied and the lowest rates of mutations and genetic counseling were found in Black and African ancestry women. This could affect their treatment options as well as their families and may make disparities worse.

Molecular Characterization of Endometrial Carcinomas in Black and White Patients Reveals Disparate Drivers with Therapeutic Implications

Abstract Although the incidence of endometrial carcinoma (EC) is similar in Black and White women, racial disparities are stark, with the highest mortality rates observed among Black patients. Here, analysis of 1,882 prospectively sequenced ECs using a clinical FDA-authorized tumor–normal panel revealed a significantly higher prevalence of high-risk histologic and molecular EC subtypes in self-identified Black (n = 259) compared with White (n = 1,623) patients. Clinically actionable alterations, including high tumor mutational burden/microsatellite instability, which confer benefit from immunotherapy, were less frequent in ECs from Black than from White patients. Ultramutated POLE molecular subtype ECs associated with favorable outcomes were rare in Black patients. Results were confirmed by genetic ancestry analysis. CCNE1 gene amplification, which is associated with aggressive clinical behavior, was more prevalent in carcinosarcomas occurring in Black than in White patients. ECs from Black and White patients display important differences in their histologic types, molecular subtypes, driver genetic alterations, and therapeutic targets. Significance: Our comprehensive analysis of prospectively clinically sequenced ECs revealed significant differences in their histologic and molecular composition and in the presence of therapeutic targets in Black versus White patients. These findings emphasize the importance of incorporating diverse populations into molecular studies and clinical trials to address EC disparities. This article is featured in Selected Articles from This Issue, p. 2293

Comprehensive analysis of germline drivers in endometrial cancer

AbstractBackgroundWe sought to determine the prevalence of germline pathogenic variants (gPVs) in unselected patients with endometrial cancer (EC), define biallelic gPVs within tumors, and describe their associations with clinicopathologic features.MethodsGermline assessment of at least 76 cancer predisposition genes was performed in patients with EC undergoing clinical tumor-normal Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) sequencing from January 1, 2015, to June 30, 2021. In patients with gPVs, biallelic alterations in ECs were identified through analysis of loss of heterozygosity and somatic PVs. Clinicopathologic variables were compared using nonparametric tests.ResultsOf 1625 patients with EC, 216 (13%) had gPVs, and 15 patients had 2 gPVs. There were 231 gPVs in 35 genes (75 [32%] high penetrance; 39 [17%] moderate penetrance; and 117 [51%] low, recessive, or uncertain penetrance). Compared with those without gPVs, patients with gPVs were younger (P = .002), more often White (P = .009), and less obese (P = .025) and had differences in distribution of tumor histology (P = .017) and molecular subtype (P < .001). Among 231 gPVs, 74 (32%) exhibited biallelic inactivation within tumors. For high-penetrance gPVs, 63% (47 of 75) of ECs had biallelic alterations, primarily affecting mismatch repair (MMR) and homologous recombination related genes, including BRCA1,BRCA2, RAD51D, and PALB2. Biallelic inactivation varied across molecular subtypes with highest rates in microsatellite instability-high (MSI-H) or copy-number (CN)–high subtypes (3 of 12 [25%] POLE, 30 of 77 [39%] MSI-H, 27 of 60 [45%] CN-high, 9 of 57 [16%] CN-low; P < .001).ConclusionsOf unselected patients with EC, 13% had gPVs, with 63% of gPVs in high-penetrance genes (MMR and homologous recombination) exhibiting biallelic inactivation, potentially driving cancer development. This supports germline assessment in EC given implications for treatment and cancer prevention.

Microsatellite Instability–High Endometrial Cancers with MLH1 Promoter Hypermethylation Have Distinct Molecular and Clinical Profiles

Abstract Purpose: Microsatellite instability–high (MSI-H) endometrial carcinomas are underpinned by distinct mechanisms of DNA mismatch repair deficiency (MMR-D). We sought to characterize the clinical and genetic features of MSI-H endometrial cancers harboring germline or somatic mutations in MMR genes or MLH1 promoter hypermethylation (MLH1ph). Experimental Design: Of > 1,100 patients with endometrial cancer that underwent clinical tumor-normal sequencing, 184 had MSI-H endometrial cancers due to somatic MMR mutations or MLH1ph, or harbored pathogenic germline MMR mutations. Clinicopathologic features, mutational landscape, and tumor-infiltrating lymphocyte (TIL) scores were compared among MMR-D groups using nonparametric tests. Log-rank tests were used for categorical associations; Kaplan–Meier method and Wald test based on Cox proportional hazards models were employed for continuous variables and survival analyses. Results: Compared with patients with germline (n = 25) and somatic (n = 39) mutations, patients with MLH1ph endometrial cancers (n = 120) were older (P < 0.001), more obese (P = 0.001) and had more advanced disease at diagnosis (P = 0.025). MLH1ph endometrial cancers were enriched for JAK1 somatic mutations as opposed to germline MMR-D endometrial cancers which showed enrichment for pathogenic ERBB2 mutations. MLH1ph endometrial cancers exhibited lower tumor mutational burden and TIL scores compared with endometrial cancers harboring germline or somatic MMR mutations (P < 0.01). MLH1ph endometrial cancer patients had shorter progression-free survival (PFS) on univariate analysis, but in multivariable models, stage at diagnosis remained the only predictor of survival. For stage I/II endometrial cancer, two-year PFS was inferior for patients with MLH1ph endometrial cancers compared with germline and somatic MMR groups (70% vs. 100%, respectively). Conclusions: MLH1ph endometrial cancers likely constitute a distinct clinicopathologic entity compared with germline and somatic MMR-D ECs with potential treatment implications.

Early age of onset and broad cancer spectrum persist in MSH6- and PMS2-associated Lynch syndrome

This study aimed to characterize MSH6/PMS2-associated mismatch repair-deficient (MMR-D)/microsatellite instability-high (MSI-H) tumors, given revised guidelines suggesting more modest phenotypes. Patients who consented to Institutional Review Board-approved protocols of tumor/germline sequencing or Lynch syndrome registry at a single institution from February 2005 to January 2021 with germline, heterozygous MSH6/PMS2 pathogenic/likely pathogenic variants were identified. Clinical data were abstracted and correlated with MMR/microsatellite instability status using nonparametric tests. We identified 243 patients (133 sequencing, 110 registry) with germline MSH6/PMS2 pathogenic/likely pathogenic variants; 186 (77%) had >1 cancer. Of 261 pooled tumors, colorectal cancer (CRC) and endometrial cancer (EC) comprised 55% and 43% of cancers in MSH6 and PMS2, respectively; 192 tumors underwent molecular assessments and 122 (64%) were MMR-D/MSI-H (77 in MSH6, 45 in PMS2). MMR-D/MSI-H cancers included CRC (n = 56), EC (n = 35), small bowel cancer (n = 6), ovarian cancer (n = 6), urothelial cancer (n = 5), pancreas/biliary cancer (n = 4), gastric/esophageal cancer (n = 3), nonmelanoma skin tumors (n = 3), prostate cancer (n = 2), breast cancer (n = 1), and central nervous system/brain cancer (n = 1). Among MMR-D/MSI-H CRC and EC, median age of diagnosis was 51.5 (range = 27-80) and 55 (range = 39-74) years, respectively; 9 of 56 (16%) MMR-D/MSI-H CRCs were diagnosed at age <35 years. MSH6/PMS2 heterozygotes remain at risk for a broad spectrum of cancers, with 16% of MMR-D/MSI-H CRCs presenting before upper threshold of initiation of colonoscopy per guidelines.

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 &lt; 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 &lt;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 &lt;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.

Factors associated with an inconclusive result from commercial homologous recombination deficiency testing in ovarian cancer

AbstractIntroductionHomologous recombination deficiency (HRD) testing is used to determine the appropriateness of poly ADP‐ribose polymerase inhibitors for patients with epithelial ovarian cancer and no germline/somatic BRCA1/2 alterations. Myriad MyChoice CDx reports a genomic instability score (GIS) to quantify the level of HRD, with a positive score defined as ≥42. The authors sought to define factors associated with obtaining an inconclusive HRD test result.MethodsGIS was retrieved for patients at their institution with epithelial ovarian cancer without germline/somatic BRCA1/2 deleterious alterations who underwent HRD testing from April 2020–August 2023. Clinical data were abstracted from the medical record.ResultsOf 477 HRD test results identified, 57 (12%) were inconclusive. High‐grade serous ovarian cancers had higher GIS than other histologic types (median 29 vs. 21, p &lt; .001). Most HRD cases were of high‐grade serous histology; no cases with clear cell or endometrioid histology were HRD‐positive. On univariate analysis, interval versus primary cytoreductive surgery, other specimen sources versus surgical specimens, and chemotherapy exposure were risk factors for inconclusive HRD testing. On multivariable analysis, chemotherapy exposure, and tissue source were associated with an inconclusive test result, with surgical specimens more likely to yield a conclusive result than other sources (biopsy, cytology, other). Age, stage, self‐reported race, and histology were not associated with an inconclusive result.ConclusionsSurgical tissue was more likely to yield a conclusive HRD test result versus other sources of epithelial ovarian cancer tissue acquisition. When feasible, laparoscopic biopsy before initiation of neoadjuvant chemotherapy may increase the likelihood of obtaining interpretable HRD test results.

Germline Pathogenic Variants and Genetic Counseling by Ancestry in Patients With Epithelial Ovarian Cancer

Mutations in ovarian cancer risk genes are found in women of diverse ancestries, supporting genetic testing for ALL

Shedding Light on PARP Inhibitor Response through Functional Imaging

Summary Functional PET imaging using a PARP inhibitor (PARPi) analog may serve as an early, dynamic biomarker of response to PARPi therapy in high-grade serous ovarian cancer. Clinically, this could help to rapidly identify PARPi nonresponders, thereby maximizing efficacy and avoiding toxicities of futile treatments. See related article by Pantel et al., p. 1515

Overcoming Barriers to Tumor Genomic Profiling through Direct-to-Patient Outreach

Abstract Purpose: To overcome barriers to genomic testing for patients with rare cancers, we initiated a program to offer free clinical tumor genomic testing worldwide to patients with select rare cancer subtypes. Experimental Design: Patients were recruited through social media outreach and engagement with disease-specific advocacy groups, with a focus on patients with histiocytosis, germ cell tumors (GCT), and pediatric cancers. Tumors were analyzed using the MSK-IMPACT next-generation sequencing assay with the return of results to patients and their local physicians. Whole-exome recapture was performed for female patients with GCTs to define the genomic landscape of this rare cancer subtype. Results: A total of 333 patients were enrolled, and tumor tissue was received for 288 (86.4%), with 250 (86.8%) having tumor DNA of sufficient quality for MSK-IMPACT testing. Eighteen patients with histiocytosis have received genomically guided therapy to date, of whom 17 (94%) have had clinical benefit with a mean treatment duration of 21.7 months (range, 6–40+). Whole-exome sequencing of ovarian GCTs identified a subset with haploid genotypes, a phenotype rarely observed in other cancer types. Actionable genomic alterations were rare in ovarian GCT (28%); however, 2 patients with ovarian GCTs with squamous transformation had high tumor mutational burden, one of whom had a complete response to pembrolizumab. Conclusions: Direct-to-patient outreach can facilitate the assembly of cohorts of rare cancers of sufficient size to define their genomic landscape. By profiling tumors in a clinical laboratory, results could be reported to patients and their local physicians to guide treatment. See related commentary by Desai and Subbiah, p. 2339

Characteristics and survival of ovarian cancer patients treated with neoadjuvant chemotherapy but not undergoing interval debulking surgery

Neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) confers similar outcomes as primary debulking surgery and chemotherapy. Little is known about patients who receive NACT but do not undergo debulking surgery. Our aim was to characterize these patients. We prospectively identified patients with newly diagnosed stage III/IV ovarian cancer treated with NACT from 7/1/15-12/1/17. Fisher exact and Wilcoxon rank-sum tests were used to compare clinical characteristics by surgical status. The Kaplan-Meier method was used to estimate survival outcomes. Log-rank test and Cox proportional hazards model were applied to assess the relationship of covariates to outcome, and time-dependent covariates were applied to variables collected after diagnosis. Of 224 women who received NACT, 162 (72%) underwent IDS and 62 (28%) did not undergo surgery. The non-surgical group was older (p<0.001), had higher Charlson comorbidity index (CCI; p<0.001), lower albumin levels (p=0.007), lower Karnofsky performance scores (p<0.001), and were more likely to have dose reductions in NACT (p<0.001). Reasons for no surgery included poor response to NACT (39%), death (15%), comorbidities (24%), patient preference (16%), and loss to follow-up (6%). The no surgery group had significantly worse overall survival (OS) than the surgery group (hazard ratio=3.34; 95% confidence interval=1.66-6.72; p<0.001), after adjustment for age, CCI, and dose reductions. A significant proportion of women treated with NACT do not undergo IDS, and these women are older, frailer, and have worse OS. More studies are needed to find optimal therapies to maximize outcomes in this high-risk, elderly population.

Risk-Reducing Bilateral Salpingo-Oophorectomy for Ovarian Cancer: A Review and Clinical Guide for Hereditary Predisposition Genes

Pathogenic germline variants underlie up to 20% of ovarian cancer (OC) and are associated with varying degrees of risk for OC. For mutations in high-penetrance genes such as BRCA1/ 2, the role of risk-reducing bilateral salpingo-oophorectomy (RRSO) in cancer prevention is well-established and improves mortality. However, in moderate-penetrance genes where the degree of risk for OC is less precisely defined, the role of RRSO is more controversial. Although national guidelines have evolved to incorporate gene-specific recommendations, studies demonstrate significant variations in practice. Given this, our multidisciplinary group has reviewed the available literature on risk estimates for genes associated with OC, incorporated levels of evidence, and set thresholds for consideration of RRSO. We found that the benefit of RRSO is well-established for pathogenic variants in BRCA1/2 as well as BRIP1 and RAD51C/ D where the risk of OC is elevated beyond our threshold for RRSO. In PALB2, RRSO is particularly controversial as newer studies consistently demonstrate an increased risk of OC that is dependent on family history, making uniform recommendations challenging. Additionally, new guidelines for Lynch syndrome provide gene-specific risks, questioning the role of RRSO, and even hysterectomy, for MSH6 and PMS2 mutation carriers. Given these uncertainties, shared decision making should be used around RRSO with discussion of individual risk factors, family history, and adverse effects of surgery and premature menopause. Herein, we provide a clinical guide and counseling points.

MAPK Pathway Genetic Alterations Are Associated with Prolonged Overall Survival in Low-Grade Serous Ovarian Carcinoma

Abstract Purpose: To characterize the somatic mutational landscape, investigate associations between genetic alterations and clinical outcomes, and determine the prevalence of pathogenic germline mutations in low-grade serous ovarian carcinomas (LGSC). Experimental Design: Patients with LGSC tumors who underwent panel-based sequencing of up to 505 genes were identified. Data on somatic and germline mutations; copy-number alterations; and clinicopathologic features, including age at diagnosis, platinum sensitivity, and overall survival (OS), were collected. Results: Following central pathology rereview, 119 patients with LGSC were identified for analysis. Of these, 110 (92%) had advanced-stage disease (stages III/IV). Somatic KRAS (33%), NRAS (11%), EIF1AX (10%), and BRAF (11%) alterations were the most common; MAPK pathway alterations were found in 60% (n = 71) of LGSCs. KRAS mutations were significantly associated with age at diagnosis more than 50 years (P = 0.02) and platinum-sensitive disease (P = 0.03). On multivariate analysis, MAPK pathway alterations (P = 0.02) and platinum sensitivity (P = 0.005) were significantly associated with improved OS. Seventy-nine patients (66%) underwent germline genetic testing; seven pathogenic germline mutations were identified: MUTYH (n = 2), BAP1 (n = 1), RB1 (n = 1), CHEK2 (n = 1), APC (n = 1), and FANCA (n = 1). There were no germline BRCA1/2 mutations. One germline MUTYH-associated LGSC harbored loss-of-heterozygosity at the MUTYH locus, and the patient with the germline BAP1 mutation also harbored a somatic BAP1 frameshift mutation. Conclusions: This study showed that MAPK pathway alterations in LGSC, including KRAS mutations, are independently associated with platinum sensitivity and prolonged survival. Germline data, which were limited, identified few pathogenic germline mutations in patients with LGSC. See related commentary by Veneziani and Oza, p. 4357

Ovarian cancer mutational processes drive site-specific immune evasion

High-grade serous ovarian cancer is a genomically complex malignancy. Here the authors integrate whole-genome sequencing, single-cell RNA sequencing, digital histopathology and multiplexed immunofluorescence across 160 tumour sites from 42 patients, revealing that mutational processes shape site-specific immune evasion.

Ongoing genome doubling shapes evolvability and immunity in ovarian cancer

Single-cell whole-genome sequencing of 30,260 tumour genomes from 70 samples across 41 patients in the SPECTRUM cohort reveals that ongoing whole-genome doubling drives tumour evolvability and immune evasion in high-grade serous ovarian cancer.