Investigator
Radboud University Medical Center
Nationwide implementation and evaluation of the Tumor‐First workflow for genetic testing in ovarian carcinoma
AbstractDespite international agreement on the importance of tumor DNA testing and germline testing for determining PARP inhibitor treatment eligibility in patients with ovarian carcinoma (OC) and for cancer prevention in their relatives, the optimal strategy remains under debate. In the Netherlands, the “Tumor‐First workflow” was initiated and implemented nationwide: a well‐validated tumor DNA test is the primary test for detecting tumor pathogenic variants (PVs) in OC risk genes (BRCA1/2, RAD51C/D, BRIP1, PALB2). The detection of tumor PVs is subsequently used to stratify germline testing and determine treatment eligibility. The Tumor‐First workflow is efficient and saves costs. The aim of this study was to evaluate the nationwide implementation of the Tumor‐First workflow. We analyzed real‐time genetic testing practices, including tumor DNA and germline testing, in patients diagnosed with OC from 2019 to 2023, as identified through the Dutch Pathology Registry (Palga). Testing data were collected from diagnostic pathology and genetic reports. Out of the 3926 OC patients, 2778 (71%) received OC tumor DNA testing as the primary test. Between 2019 and 2023, this percentage increased from 50% to 85%. Of these tumor DNA tests, 2703 (97%) were successful, with 398 (15%) resulting in the identification of a PV in an OC risk gene. Most of these patients (291; 73%) underwent germline testing, and 147 (51%) were found to have a germline PV. We conclude that the nationwide implementation of the Tumor‐First workflow for OC was effective. Multidisciplinary efforts contributed to a more efficient detection of germline and somatic PVs in OC risk genes.
Genomic instability in non–breast or ovarian malignancies of individuals with germline pathogenic variants in BRCA1/2
Abstract Background Individuals with germline pathogenic variants in BRCA1 or BRCA2 are at a high risk of breast and ovarian carcinomas with BRCA1/2 deficiency and homologous recombination deficiency that can be detected by analysis of genome-wide genomic instability features such as large-scale state transitions, telomeric allelic imbalances, and genomic loss of heterozygosity. Malignancies with homologous recombination deficiency are more sensitive to platinum-based therapies and poly(ADP-ribose) polymerase inhibitors. We investigated the fraction of non–breast or ovarian malignancies that have BRCA1/2 deficiency and genomic instability features. Methods The full tumor history of a large, historical, clinic-based, consecutive cohort of 2965 individuals with germline pathogenic variants in BRCA1/2 was retrieved from the Dutch nationwide pathology databank (Palga). In total, 169 non–breast or ovarian malignancies were collected and analyzed using targeted next-generation sequencing and shallow whole-genome sequencing to determine somatic second-hit alterations and genomic instabilities indicative of homologous recombination deficiency, respectively. Results BRCA1/2 deficiency was detected in 27% (21/79) and 23% (21/90) of 20 different types of non–breast or ovarian malignancies in individuals with germline pathogenic variants in BRCA1 and BRCA2, respectively. These malignancies had a higher genomic instability score than BRCA1- or BRCA2-proficient malignancies (P < .001 and P < .001, respectively). Conclusions BRCA1/2 deficiency and genomic instability features were found in 27% and 23% of a broad spectrum of non–breast or ovarian malignancies in individuals with germline pathogenic variants in BRCA1 and BRCA2, respectively. Evaluation of the effectiveness of poly(ADP-ribose) polymerase inhibitors in these individuals should be focused on tumors with a confirmed absence of a wild-type allele.
Microsatellite instability in noncolorectal and nonendometrial malignancies in patients with Lynch syndrome
Abstract Background Individuals with Lynch syndrome are at increased hereditary risk of colorectal and endometrial carcinomas with microsatellite instability (MSI-H) and mismatch repair-deficiency (dMMR), which make these tumors vulnerable to therapy with immune checkpoint inhibitors. Our aim is to assess how often other tumor types in these individuals share these characteristics. Methods We retrieved the full tumor history of a historical clinic-based cohort of 1745 individuals with Lynch syndrome and calculated the standardized incidence ratio for all tumor types. MSI status, somatic second hit alterations, and immunohistochemistry-based MMR status were analyzed in 236 noncolorectal and nonendometrial malignant tumors. Results In individuals with Lynch syndrome MSI-H/dMMR occurred both in Lynch-spectrum and in non–Lynch-spectrum malignancies (85% vs 37%, P < .01). MSI-H/dMMR malignancies were found in nearly all non–Lynch-spectrum tumor types. A high percentage (33%) of breast carcinomas with medullary features was observed, and most of them were MSI-H/dMMR. Breast carcinoma with medullary features were shown to be associated with Lynch syndrome (standardized incidence ratio = 38.8, 95% confidence interval = 16.7 to 76.5). Conclusions In individuals with Lynch syndrome, MSI-H/dMMR occurs in more than one-half of the malignancies other than colorectal and endometrial carcinomas, including tumor types without increased incidence. The Lynch-spectrum tumors should be expanded to breast carcinomas with medullary features. All malignancies in patients with Lynch syndrome, independent of subtype, should be tested for MSI-H/dMMR in case therapy with immune checkpoint inhibitors is considered. Moreover, Lynch syndrome should be considered an underlying cause of all MSI-H/dMMR malignancies other than colorectal and endometrial carcinomas.
Two types of primary mucinous ovarian tumors can be distinguished based on their origin
The origin of primary mucinous ovarian tumors is unknown. We explore the hypothesis that they originate from either Brenner tumors or teratomas and examine differences between the tumors that arise in these settings. A total of 104 Brenner tumor-associated mucinous tumors and 58 teratoma-associated mucinous tumors were analyzed. Immunohistochemistry for 21 antigens and fluorescence in situ hybridization for ERBB2 and MYC were performed. Genome-wide copy number analysis and mutation analysis for 56 cancer-related genes was carried out on a subset of mucinous ovarian tumors and their complementary Brenner tumor or teratoma. Patients with teratoma-associated mucinous tumors were significantly younger than patients with Brenner tumor-associated mucinous tumors (43 vs. 61 years). During progression from cystadenoma to atypical proliferative mucinous (borderline) tumor to carcinoma expression of typical gastrointestinal markers was increased in both Brenner tumor-associated and teratoma-associated mucinous tumors. Brenner tumor-associated mucinous tumors showed more frequently calcifications and Walthard cell nests, rarely expressed SATB2 and showed more often co-deletion of CDKN2A and MTAP. Teratoma-associated mucinous tumors were characterized by mucinous stromal dissection, SATB2 expression and RNF43 mutations. Other frequent mutations in both Brenner tumor-associated and teratoma-associated mucinous tumors were TP53 and KRAS mutations. Based on identical mutations or copy number profiles clonal relationships were indicated in two mucinous tumors and their associated Brenner tumor. Teratomas and Brenner tumors give rise to different subtypes of mucinous ovarian tumors. Subsequent progression pathways are comparable since both Brenner tumor-associated and teratoma-associated mucinous tumors develop a gastrointestinal immunophenotype during progression and show early mutations in KRAS and TP53. Teratoma-associated mucinous tumors may more closely resemble true gastrointestinal tumors, indicated by their expression of SATB2 and the presence of RNF43 mutations.
Response to Tomao, Panici, and Tomao
Evaluation of homologous recombination testing in ovarian carcinoma.
Abstract Homologous recombination deficiency (HRD) testing may be used to stratify ovarian carcinoma (OC) patients for PARP inhibitor therapy. In the Netherlands, different NGS-based assays are used to assess genomic instability as a hallmark of HRD. We evaluated the uniformity of HRD testing. Firstly, interlaboratory assessments of 10 tumors were performed in 8 centers. 71 out of the 77 (92%) successful tests were concordant. Results were more consistent in OC with a pathogenic variation (PV) or promoter methylation of a homologous recombination repair (HRR) gene (97%) than in those without (87%). Secondly, concordance between BRCA1 / RAD51C promoter methylation and HRD was assessed in 244 samples without a PV in HRR genes. BRCA1 / RAD51C promoter methylation was present in 38 out of 100 (38%) samples classified as HRD, and absent in all ( n = 144) non-HRD samples ( p < 0.001). Lastly, pathology reports from 765 HRD tests were reviewed to evaluate routine diagnostics. Testing was successful in 695 (91%) cases. HRD detection rates were higher in high-grade serous OC compared to other histological subtypes (49% versus 12%, p < 0.001). The five HRD assays varied significantly in HRD detection rates in high-grade serous OC. The results support the applicability of genomic instability analyses to assess HRD, while also highlighting the need to improve harmonization across different assays when HRD is used for therapeutic decision making.
