Integration of Germline Genetic Testing Into Routine Clinical Practice for Patients With Pancreatic Adenocarcinoma.

PURPOSE: Germline genetic testing (GT) is recommended for all patients with pancreatic ductal adenocarcinoma (PDAC), but the traditional clinical genetics infrastructure is limited in addressing the unique needs of this population. We describe the integration of point of care (POC) GT into routine clinical practice for all patients with PDAC at an academic medical center. METHODS: We developed a clinical POC workflow that leverages electronic health record (EHR) tools and behavioral nudges to enhance the sustainability and scalability of our previously described research-based POC model. For each of the research and clinical POC cohorts, we calculated the percentage of eligible patients who underwent GT. We used Wilcoxon rank-sum and Pearson's chi-squared tests to compare patients who did and did not undergo GT. We conducted surveys among oncology clinicians to evaluate the acceptability, appropriateness, and feasibility of the clinical POC model. RESULTS: The research POC cohort included 905 patients, of whom 694 (76.7%) underwent GT. The clinical POC cohort included 148 patients, of whom 126 (85.1%) underwent GT. Patients who underwent GT in the research POC cohort were significantly younger (median age, 67.0 v 70.9 years; P = .031) and more likely to be White (82.1% v 68.7%; P < .001) and commercially insured (41.8% v 28.0%; P < .001) compared with those who did not; there were no significant differences between GT groups in the clinical POC cohort. Oncology clinicians found the clinical POC model to be acceptable (mean 4.4/5), appropriate (4.6/5), feasible (4.0/5), and have a positive impact on their patients (4.9/5). CONCLUSION: A clinical POC model leveraging EHR tools and behavioral nudges is acceptable, appropriate, feasible, and associated with a >85% GT rate among patients with PDAC.

Prevalence of H. pylori and Gastric Intestinal Metaplasia in BRCA1 and BRCA2 Carriers.

BRCA1 and BRCA2 carriers may be at increased risk for gastric cancer; however, the mechanisms of gastric carcinogenesis remain poorly understood. We sought to determine the prevalence of gastric cancer risk factors Helicobacter pylori (H. pylori) infection and gastric intestinal metaplasia (GIM) among BRCA1/2 carriers to gain insight into the pathogenesis of gastric cancer in this population. A total of 100 unselected BRCA1/2 carriers who underwent endoscopic ultrasound from March 2022 to March 2023 underwent concomitant upper endoscopy with nontargeted gastric antrum and body biopsies. The study population (70% women; mean age 60.1 years) included 66% BRCA2 carriers. H. pylori was detected in one (1%) individual, 7 (7%) had GIM, 2 (2%) had autoimmune atrophic gastritis, and no gastric cancers were diagnosed. Among BRCA1/2 carriers, H. pylori prevalence was low and GIM prevalence was similar to that in the general population; however, identification of H. pylori or GIM may help inform future gastric cancer risk management strategies in BRCA1/2 carriers. Prevention Relevance: Evaluating the burden of H. pylori infection and GIM among BRCA1/2 carriers is warranted to better understand the mechanisms of gastric carcinogenesis and to help inform risk management strategies for gastric cancer among this at-risk population.

Clinical management of TP53 mosaic variants found on germline genetic testing.

BACKGROUND: Germline heterozygous TP53 pathogenic variants (PVs) cause Li Fraumeni Syndrome (LFS, OMIM#151623). TP53 PVs at lower-than-expected variant allele frequencies (VAF) may reflect postzygotic mosaicism (PZM) or clonal hematopoiesis (CH); however, no guidelines exist for workup and clinical management. PATIENTS AND METHODS: Retrospective analysis of probands who presented to an academic cancer genetics program with a TP53 PV result on germline genetic testing. RESULTS: Twenty-one of 125 unrelated probands (17 %) were found to harbor a TP53 PV with VAF<30 % or a designation of "mosaic". A diagnosis of PZM was made in nine (43 %) due to a clinical phenotype consistent with LFS with (n = 8) or without (n = 1) positive ancillary tissue testing. Twelve patients (57 %) were diagnosed with presumed CH (pCH) due to a diagnosis of a myeloproliferative neoplasm, negative ancillary tissue testing, clinical phenotype not meeting LFS criteria, no cancer, and/or no first cancer age<50. Of the 19 patients with biological offspring, nine had either partial or complete offspring testing, all negative. CONCLUSIONS: Determining the etiology of low VAF TP53 PVs requires ancillary tissue testing and incorporation of clinical phenotype. Discerning PZM versus CH is important to provide optimal care and follow-up.

Advancing Cancer Interception.

Rapid advances in technology and therapeutics, along with better methods to discern who is at risk for cancer by genetic testing and other means, has enabled the development of cancer interception. Targeted therapies and "immuno-interception" may eliminate premalignant lesions and require clinical trial and treatment paradigms altogether distinct from current approaches.

Large-scale genome-wide association study of 398,238 women unveils seven novel loci associated with high-grade serous epithelial ovarian cancer risk.

Background: Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We used data from the Ovarian Cancer Association Consortium (OCAC), Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA), UK Biobank (UKBB), and FinnGen to identify novel HGSOC susceptibility loci and develop polygenic scores (PGS). Methods: We analyzed >22 million variants for 398,238 women. Associations were assessed separately by consortium and meta-analysed. OCAC and CIMBA data were used to develop PGS which were trained on FinnGen data and validated in UKBB and BioBank Japan. Results: Eight novel variants were associated with HGSOC risk. An interesting discovery biologically was finding that TP53 3'-UTR SNP rs78378222 was associated with HGSOC (per T allele relative risk (RR)=1.44, 95%CI:1.28-1.62, P=1.76×10-9). The optimal PGS included 64,518 variants and was associated with an odds ratio of 1.46 (95%CI:1.37-1.54) per standard deviation in the UKBB validation (AUROC curve=0.61, 95%CI:0.59-0.62). Conclusions: This study represents the largest GWAS for HGSOC to date. The results highlight that improvements in imputation reference panels and increased sample sizes can identify HGSOC associated variants that previously went undetected, resulting in improved PGS. The use of updated PGS in cancer risk prediction algorithms will then improve personalized risk prediction for HGSOC.

Patient-Reported Outcomes in OlympiA: A Phase III, Randomized, Placebo-Controlled Trial of Adjuvant Olaparib in gBRCA1/2 Mutations and High-Risk Human Epidermal Growth Factor Receptor 2-Negative Early Breast Cancer.

PURPOSE: The OlympiA randomized phase III trial compared 1 year of olaparib (OL) or placebo (PL) as adjuvant therapy in patients with germline BRCA1/2, high-risk human epidermal growth factor receptor 2-negative early breast cancer after completing (neo)adjuvant chemotherapy ([N]ACT), surgery, and radiotherapy. The patient-reported outcome primary hypothesis was that OL-treated patients may experience greater fatigue during treatment. METHODS: Data were collected before random assignment, and at 6, 12, 18, and 24 months. The primary end point was fatigue, measured with the Functional Assessment of Chronic Illness Therapy-Fatigue scale. Secondary end points, assessed with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, Core 30 item, included nausea and vomiting (NV), diarrhea, and multiple functional domains. Scores were compared between treatment groups using mixed model for repeated measures. Two-sided P values <.05 were statistically significant for the primary end point. All secondary end points were descriptive. RESULTS: One thousand five hundred and thirty-eight patients (NACT: 746, ACT: 792) contributed to the analysis. Fatigue severity was statistically significantly greater for OL versus PL, but not clinically meaningfully different by prespecified criteria (≥3 points) at 6 months (diff OL v PL: NACT: -1.3 [95% CI, -2.4 to -0.2]; P = .022; ACT: -1.3 [95% CI, -2.3 to -0.2]; P = .017) and 12 months (NACT: -1.6 [95% CI, -2.8 to -0.3]; P = .017; ACT: -1.3 [95% CI, -2.4 to -0.2]; P = .025). There were no significant differences in fatigue severity between treatment groups at 18 and 24 months. NV severity was worse in patients treated with OL compared with PL at 6 months (NACT: 6.0 [95% CI, 4.1 to 8.0]; ACT: 5.3 [95% CI, 3.4 to 7.2]) and 12 months (NACT: 6.4 [95% CI, 4.4 to 8.3]; ACT: 4.5 [95% CI, 2.8 to 6.1]). During treatment, there were some clinically meaningful differences between groups for other symptoms but not for function subscales or global health status. CONCLUSION: Treatment-emergent symptoms from OL were limited, generally resolving after treatment ended. OL- and PL-treated patients had similar functional scores, slowly improving during the 24 months after (N)ACT and there was no clinically meaningful persistence of fatigue severity in OL-treated patients.

Functional analysis and clinical classification of 462 germline BRCA2 missense variants affecting the DNA binding domain.

Variants of uncertain significance (VUSs) in BRCA2 are a common result of hereditary cancer genetic testing. While more than 4,000 unique VUSs, comprised of missense or intronic variants, have been identified in BRCA2, the few missense variants now classified clinically as pathogenic or likely pathogenic are predominantly located in the region encoding the C-terminal DNA binding domain (DBD). We report on functional evaluation of the influence of 462 BRCA2 missense variants affecting the DBD on DNA repair activity of BRCA2 using a homology-directed DNA double-strand break repair assay. Of these, 137 were functionally abnormal, 313 were functionally normal, and 12 demonstrated intermediate function. Comparisons with other functional studies of BRCA2 missense variants yielded strong correlations. Sequence-based in silico prediction models had high sensitivity, but limited specificity, relative to the homology-directed repair assay. Combining the functional results with clinical and genetic data in an American College of Medical Genetics (ACMG)/Association for Molecular Pathology (AMP)-like variant classification framework from a clinical testing laboratory, after excluding known splicing variants and functionally intermediate variants, classified 431 of 442 (97.5%) missense variants (129 as pathogenic/likely pathogenic and 302 as benign/likely benign). Functionally abnormal variants classified as pathogenic by ACMG/AMP rules were associated with a slightly lower risk of breast cancer (odds ratio [OR] 5.15, 95% confidence interval [CI] 3.43-7.83) than BRCA2 DBD protein truncating variants (OR 8.56, 95% CI 6.03-12.36). Overall, functional studies of BRCA2 variants using validated assays substantially improved the variant classification yield from ACMG/AMP models and are expected to improve clinical management of many individuals found to harbor germline BRCA2 missense VUS.

Olaparib plus Durvalumab, with or without Bevacizumab, as Treatment in PARP Inhibitor-Naïve Platinum-Sensitive Relapsed Ovarian Cancer: A Phase II Multi-Cohort Study.

PURPOSE: Early results from the phase II MEDIOLA study (NCT02734004) in germline BRCA1- and/or BRCA2-mutated (gBRCAm) platinum-sensitive relapsed ovarian cancer (PSROC) showed promising efficacy and safety with olaparib plus durvalumab. We report efficacy and safety of olaparib plus durvalumab in an expansion cohort of women with gBRCAm PSROC (gBRCAm expansion doublet cohort) and two cohorts with non-gBRCAm PSROC, one of which also received bevacizumab (non-gBRCAm doublet and triplet cohorts). PATIENTS AND METHODS: In this open-label, multicenter study, PARP inhibitor-naïve patients received olaparib plus durvalumab treatment until disease progression; the non-gBRCAm triplet cohort also received bevacizumab. Primary endpoints were objective response rate (ORR; gBRCAm expansion doublet cohort), disease control rate (DCR) at 24 weeks (non-gBRCAm cohorts), and safety (all cohorts). RESULTS: The full analysis and safety analysis sets comprised 51, 32, and 31 patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively. ORR was 92.2% [95% confidence interval (CI), 81.1-97.8] in the gBRCAm expansion doublet cohort (primary endpoint); DCR at 24 weeks was 28.1% (90% CI, 15.5-43.9) in the non-gBRCAm doublet cohort (primary endpoint) and 74.2% (90% CI, 58.2-86.5) in the non-gBRCAm triplet cohort (primary endpoint). Grade ≥ 3 adverse events were reported in 47.1%, 65.6%, and 61.3% of patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively, most commonly anemia. CONCLUSIONS: Olaparib plus durvalumab continued to show notable clinical activity in women with gBRCAm PSROC. Olaparib plus durvalumab with bevacizumab demonstrated encouraging clinical activity in women with non-gBRCAm PSROC. No new safety signals were identified.

Germline Genetic Testing for Hereditary Breast and Ovarian Cancer: Current Concepts in Risk Evaluation.

Our understanding of hereditary breast and ovarian cancer has significantly improved over the past two decades. In addition to BRCA1/2, pathogenic variants in several other DNA-repair genes have been shown to increase the risks of breast and ovarian cancer. The magnitude of cancer risk is impacted not only by the gene involved, but also by family history of cancer, polygenic risk scores, and, in certain genes, pathogenic variant type or location. While estimates of breast and ovarian cancer risk associated with pathogenic variants are available, these are predominantly based on studies of high-risk populations with young age at diagnosis of cancer, multiple primary cancers, or family history of cancer. More recently, breast cancer risk for germline pathogenic variant carriers has been estimated from population-based studies. Here, we provide a review of the field of germline genetic testing and risk evaluation for hereditary breast and ovarian cancers in high-risk and population-based settings.

Analysis of BRCA1- and BRCA2-Related Pancreatic Cancer and Survival.

This cohort study compares the outcomes of patients with BRCA1 and BRCA-related pancreatic cancers using 2 large data sets.

Protocol to evaluate sequential electronic health record-based strategies to increase genetic testing for breast and ovarian cancer risk across diverse patient populations in gynecology practices.

BACKGROUND: Germline genetic testing is recommended by the National Comprehensive Cancer Network (NCCN) for individuals including, but not limited to, those with a personal history of ovarian cancer, young-onset (< 50 years) breast cancer, and a family history of ovarian cancer or male breast cancer. Genetic testing is underused overall, and rates are consistently lower among Black and Hispanic populations. Behavioral economics-informed implementation strategies, or nudges, directed towards patients and clinicians may increase the use of this evidence-based clinical practice. METHODS: Patients meeting eligibility for germline genetic testing for breast and ovarian cancer will be identified using electronic phenotyping algorithms. A pragmatic cohort study will test three sequential strategies to promote genetic testing, two directed at patients and one directed at clinicians, deployed in the electronic health record (EHR) for patients in OB-GYN clinics across a diverse academic medical center. We will use rapid cycle approaches informed by relevant clinician and patient experiences, health equity, and behavioral economics to optimize and de-risk our strategies and methods before trial initiation. Step 1 will send patients messages through the health system patient portal. For non-responders, step 2 will reach out to patients via text message. For non-responders, Step 3 will contact patients' clinicians using a novel "pend and send" tool in the EHR. The primary implementation outcome is engagement with germline genetic testing for breast and ovarian cancer predisposition, defined as a scheduled genetic counseling appointment. Patient data collected through the EHR (e.g., race/ethnicity, geocoded address) will be examined as moderators of the impact of the strategies. DISCUSSION: This study will be one of the first to sequentially examine the effects of patient- and clinician-directed strategies informed by behavioral economics on engagement with breast and ovarian cancer genetic testing. The pragmatic and sequential design will facilitate a large and diverse patient sample, allow for the assessment of incremental gains from different implementation strategies, and permit the assessment of moderators of strategy effectiveness. The findings may help determine the impact of low-cost, highly transportable implementation strategies that can be integrated into healthcare systems to improve the use of genomic medicine. TRIAL REGISTRATION: ClinicalTrials.gov. NCT05721326. Registered February 10, 2023. https://www. CLINICALTRIALS: gov/study/NCT05721326.

NCCN Guidelines® Insights: Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 2.2024.

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic focus primarily on assessment of pathogenic/likely pathogenic (P/LP) variants associated with increased risk of breast, ovarian, pancreatic, and prostate cancer, including BRCA1, BRCA2, CDH1, PALB2, PTEN, and TP53, and recommended approaches to genetic counseling/testing and care strategies in individuals with these P/LP variants. These NCCN Guidelines Insights summarize important updates regarding: (1) a new section for transgender, nonbinary and gender diverse people who have a hereditary predisposition to cancer focused on risk reduction strategies for ovarian cancer, uterine cancer, prostate cancer, and breast cancer; and (2) testing criteria and management associated with TP53 P/LP variants and Li-Fraumeni syndrome.

Development of an Electronic Health Record-Based Clinical Decision Support Tool for Patients With Lynch Syndrome.

PURPOSE: To develop an electronic health record (EHR)-based clinical decision support (CDS) tool to promote guideline-recommended cancer risk management among patients with Lynch syndrome (LS), an inherited cancer syndrome that confers an increased risk of colorectal and other cancer types. MATERIALS AND METHODS: We conducted a cross-sectional study to determine the baseline prevalence and predictors of guideline-recommended colonic surveillance and annual genetics program visits among patients with LS. Multivariable log-binomial regressions estimated prevalence ratios (PRs) of cancer risk management adherence by baseline sociodemographic and clinical characteristics. These analyses provided rationale for the development of an EHR-based CDS tool to support patients and clinicians with LS-related endoscopic surveillance and annual genetics program visits. The CDS leverages an EHR platform linking discrete genetic data to LS Genomic Indicators, in turn driving downstream clinician- and patient-facing CDS. RESULTS: Among 323 patients with LS, cross-sectional adherence to colonic surveillance and annual genetics program visits was 69.3% and 55.4%, respectively. Patients with recent electronic patient portal use were more likely to be adherent to colonic surveillance (PR, 1.67; 95% CI, 1.11 to 2.52). Patients more recently diagnosed with LS were more likely to be adherent to annual genetics program visits (PR, 0.58; 95% CI, 0.44 to 0.76 for 2-4 years; PR, 0.62; 95% CI, 0.51 to 0.75 for ≥4 compared with <2 years). Our EHR-based CDS tool is now active for 421 patients with LS throughout our health system. CONCLUSION: We have successfully developed an EHR-based CDS tool to promote guideline-recommended cancer risk management among patients with LS.

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.

Uptake of Genetic Research Results and Patient-Reported Outcomes With Return of Results Incorporating Web-Based Predisclosure Education.

PURPOSE: We developed a web-based education intervention as an alternative to predisclosure education with a genetic counselor (GC) to reduce participant burden and provider costs with return of genetic research results. METHODS: Women at three sites who participated in 11 gene discovery research studies were contacted to consider receiving cancer genetic research results. Participants could complete predisclosure education through web education or with a GC. Outcomes included uptake of research results, factors associated with uptake, and patient-reported outcomes. RESULTS: Of 819 participants, 178 actively (21.7%) and 167 passively (20.4%) declined return of results; 474 (57.9%) were enrolled. Most (60.3%) received results although this was lower than the 70% uptake we hypothesized. Passive and active decliners were more likely to be Black, to have less education, and to have not received phone follow-up after the invitation letter. Most participants selected web education (88.5%) as an alternative to speaking with a GC, but some did not complete or receive results. Knowledge increased significantly from baseline to other time points with no significant differences between those who received web versus GC education. There were no significant increases in distress between web and GC education. CONCLUSION: Interest in web-based predisclosure education for return of genetic research results was high although it did not increase uptake of results. We found no negative patient-reported outcomes with web education, suggesting that it is a viable alternative delivery model for reducing burdens and costs of returning genetic research results. Attention to attrition and lower uptake of results among Black participants and those with less formal education are important areas for future research.

The Clinical Implications of Reversions in Patients with Advanced Pancreatic Cancer and Pathogenic Variants in BRCA1, BRCA2, or PALB2 after Progression on Rucaparib.

PURPOSE: PARP inhibitors (PARPi) provide an effective maintenance option for patients with BRCA- or PALB2-mutated pancreatic cancer. However, mechanisms of PARPi resistance and optimal post-PARPi therapeutic strategies are poorly characterized. EXPERIMENTAL DESIGN: We collected paired cell-free DNA samples and post-PARPi clinical data on 42 patients with advanced, platinum-sensitive pancreatic cancer who were treated with maintenance rucaparib on NCT03140670, of whom 32 developed progressive disease. RESULTS: Peripherally detected, acquired BRCA or PALB2 reversion variants were uncommon (5/30; 16.6%) in patients who progressed on rucaparib. Reversions were significantly associated with rapid resistance to PARPi treatment (median PFS, 3.7 vs. 12.5 months; P = 0.001) and poor overall survival (median OS, 6.2 vs. 23.0 months; P < 0.0001). All patients with reversions received rechallenge with platinum-based chemotherapy following PARPi progression and experienced faster progression on this therapy than those without reversion variants (real-world time-to-treatment discontinuation, 2.4 vs. 5.8 months; P = 0.004). Of the patients who progressed on PARPi and received further chemotherapy, the OS from initiation of second-line therapy was significantly lower in those with reversion variants than in those without (5.5 vs. 12.0 months, P = 0.002). Finally, high levels of tumor shedding were independently associated with poor outcomes in patients who received rucaparib. CONCLUSIONS: Acquired reversion variants were uncommon but detrimental in a population of patients with advanced BRCA- or PALB2-related pancreatic ductal adenocarcinoma who received maintenance rucaparib. Reversion variants led to rapid progression on PARPi, rapid failure of subsequent platinum-based treatment, and poor OS of patients. The identification of such variants in the blood may have both predictive and prognostic value. See related commentary by Tsang and Gallinger, p. 5005.

Identification of BRCA1/2 mutation female carriers using circulating microRNA profiles.

Identifying germline BRCA1/2 mutation carriers is vital for reducing their risk of breast and ovarian cancer. To derive a serum miRNA-based diagnostic test we used samples from 653 healthy women from six international cohorts, including 350 (53.6%) with BRCA1/2 mutations and 303 (46.4%) BRCA1/2 wild-type. All individuals were cancer-free before and at least 12 months after sampling. RNA-sequencing followed by differential expression analysis identified 19 miRNAs significantly associated with BRCA mutations, 10 of which were ultimately used for classification: hsa-miR-20b-5p, hsa-miR-19b-3p, hsa-let-7b-5p, hsa-miR-320b, hsa-miR-139-3p, hsa-miR-30d-5p, hsa-miR-17-5p, hsa-miR-182-5p, hsa-miR-421, hsa-miR-375-3p. The final logistic regression model achieved area under the receiver operating characteristic curve 0.89 (95% CI: 0.87-0.93), 93.88% sensitivity and 80.72% specificity in an independent validation cohort. Mutated gene, menopausal status or having preemptive oophorectomy did not affect classification performance. Circulating microRNAs may be used to identify BRCA1/2 mutations in patients of high risk of cancer, offering an opportunity to reduce screening costs.

Functional and Clinical Characterization of Variants of Uncertain Significance Identifies a Hotspot for Inactivating Missense Variants in RAD51C.

Pathogenic protein-truncating variants of RAD51C, which plays an integral role in promoting DNA damage repair, increase the risk of breast and ovarian cancer. A large number of RAD51C missense variants of uncertain significance (VUS) have been identified, but the effects of the majority of these variants on RAD51C function and cancer predisposition have not been established. Here, analysis of 173 missense variants by a homology-directed repair (HDR) assay in reconstituted RAD51C-/- cells identified 30 nonfunctional (deleterious) variants, including 18 in a hotspot within the ATP-binding region. The deleterious variants conferred sensitivity to cisplatin and olaparib and disrupted formation of RAD51C/XRCC3 and RAD51B/RAD51C/RAD51D/XRCC2 complexes. Computational analysis indicated the deleterious variant effects were consistent with structural effects on ATP-binding to RAD51C. A subset of the variants displayed similar effects on RAD51C activity in reconstituted human RAD51C-depleted cancer cells. Case-control association studies of deleterious variants in women with breast and ovarian cancer and noncancer controls showed associations with moderate breast cancer risk [OR, 3.92; 95% confidence interval (95% CI), 2.18-7.59] and high ovarian cancer risk (OR, 14.8; 95% CI, 7.71-30.36), similar to protein-truncating variants. This functional data supports the clinical classification of inactivating RAD51C missense variants as pathogenic or likely pathogenic, which may improve the clinical management of variant carriers. SIGNIFICANCE: Functional analysis of the impact of a large number of missense variants on RAD51C function provides insight into RAD51C activity and information for classification of the cancer relevance of RAD51C variants.

PREDICT validity for prognosis of breast cancer patients with pathogenic BRCA1/2 variants.

We assessed the PREDICT v 2.2 for prognosis of breast cancer patients with pathogenic germline BRCA1 and BRCA2 variants, using follow-up data from 5453 BRCA1/2 carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and the Breast Cancer Association Consortium (BCAC). PREDICT for estrogen receptor (ER)-negative breast cancer had modest discrimination for BRCA1 carrier patients overall (Gönen & Heller unbiased concordance 0.65 in CIMBA, 0.64 in BCAC), but it distinguished clearly the high-mortality group from lower risk categories. In an analysis of low to high risk categories by PREDICT score percentiles, the observed mortality was consistently lower than the expected mortality, but the confidence intervals always included the calibration slope. Altogether, our results encourage the use of the PREDICT ER-negative model in management of breast cancer patients with germline BRCA1 variants. For the PREDICT ER-positive model, the discrimination was slightly lower in BRCA2 variant carriers (concordance 0.60 in CIMBA, 0.65 in BCAC). Especially, inclusion of the tumor grade distorted the prognostic estimates. The breast cancer mortality of BRCA2 carriers was underestimated at the low end of the PREDICT score distribution, whereas at the high end, the mortality was overestimated. These data suggest that BRCA2 status should also be taken into consideration with tumor characteristics, when estimating the prognosis of ER-positive breast cancer patients.