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Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.

ABSTRACT: Breast cancer patients with BRCA1/2-driven tumors may benefit from targeted therapy. It is not clear whether current BRCA screening guidelines are effective at identifying these patients. The purpose of our study was to evaluate the prevalence of inherited BRCA1/2 pathogenic variants in a large, clinically representative breast cancer cohort and to estimate the proportion of BRCA1/2 carriers not detected by selectively screening individuals with the highest probability of being carriers according to current clinical guidelines. The study included 5,122 unselected Swedish breast cancer patients diagnosed from 2001 to 2008. Target sequence enrichment (48.48 Fluidigm Access Arrays) and sequencing were performed (Illumina Hi-Seq 2,500 instrument, v4 chemistry). Differences in patient and tumor characteristics of BRCA1/2 carriers who were already identified as part of clinical BRCA1/2 testing routines and additional BRCA1/2 carriers found by sequencing the entire study population were compared using logistic regression models. Ninety-two of 5,099 patients with valid variant calls were identified as BRCA1/2 carriers by screening all study participants (1.8%). Only 416 study participants (8.2%) were screened as part of clinical practice, but this identified 35 out of 92 carriers (38.0%). Clinically identified carriers were younger, less likely postmenopausal and more likely to be associated with familiar ovarian cancer compared to the additional carriers identified by screening all patients. More BRCA2 (34/42, 81.0%) than BRCA1 carriers (23/50, 46%) were missed by clinical screening. In conclusion, BRCA1/2 mutation prevalence in unselected breast cancer patients was 1.8%. Six in ten BRCA carriers were not detected by selective clinical screening of individuals.

SUBMITTER: Li J

PROVIDER: S-EPMC6320715 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.

Li Jingmei J Wen Wei Xiong WX Eklund Martin M Kvist Anders A Eriksson Mikael M Christensen Helene Nordahl HN Torstensson Astrid A Bajalica-Lagercrantz Svetlana S Dunning Alison M AM Decker Brennan B Allen Jamie J Luccarini Craig C Pooley Karen K Simard Jacques J Dorling Leila L Easton Douglas F DF Teo Soo-Hwang SH Hall Per P Borg Åke Å Grönberg Henrik H Czene Kamila K

International journal of cancer 20181109 5

Breast cancer patients with BRCA1/2-driven tumors may benefit from targeted therapy. It is not clear whether current BRCA screening guidelines are effective at identifying these patients. The purpose of our study was to evaluate the prevalence of inherited BRCA1/2 pathogenic variants in a large, clinically representative breast cancer cohort and to estimate the proportion of BRCA1/2 carriers not detected by selectively screening individuals with the highest probability of being carriers accordin ...[more]

PMID: 30175445

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Project description:BackgroundThe prevalence of BRCA1/2 variants in Chinese breast cancer patients varies among studies. Germline or somatic BRCA1/2 mutations are associated with sensitivity to poly(ADP-ribose) polymerase-1 inhibitors and DNA-damaging agents. We aimed to investigate the distribution of both somatic and germline BRCA1/2 variants in unselected Chinese breast cancer patients, and explore their roles in tumor phenotype and disease prognosis.Methods507 breast cancer patients, unselected for family history of breast cancer or age at diagnosis, were prospectively enrolled from West China Hospital between Feb. 2008 and Feb. 2014. BRCA1/2 variants in the exons/flanking regions were detected in fresh-frozen tumors using next-generation sequencing and confirmed by independent methods. Germline/somatic status was validated by Sanger sequencing in paired blood/normal tissue.ResultsBRCA1/2 pathogenic or likely pathogenic (P/LP) variants were detected in 50 patients (9.9%), including 40 germline carriers (18 in BRCA1, 22 in BRCA2), 9 patients with somatic variants (3 in BRCA1, 6 in BRCA2), and 1 patient with concurrent germline/somatic variants in BRCA2. The triple-negative (21.4%) and Luminal B (9.7%) subtypes had higher rates of BRCA1/2 variants. In patients with disease stage 0~II, presence of a germline or somatic BRCA1 P/LP variant increased the risk of relapse as compared to non-carriers [univariate hazard ratio (HR): 3.70, P = 0.04]. Germline BRCA1 P/LP variants, which were associated with aggressive tumor phenotypes, predicted worse disease-free survival in the subgroup of stage 0~II (HR: 4.52, P = 0.02) and N0 (HR: 5.4, P = 0.04) compared to non-carriers.ConclusionA high frequency of germline and somatic BRCA1/2 P/LP variants was detected in unselected Chinese breast cancer patients. Luminal B subtype should be considered as a high-risk population of BRCA1/2 mutation, in addition to triple-negative breast cancer. BRCA1 status was associated with aggressive tumor phenotype and worse disease progression in early stage breast cancer patients.

Project description:ImportanceThe clinical importance of genetic testing of BRCA1 and BRCA2 in breast, ovarian, prostate, and pancreatic cancers is widely recognized. However, there is insufficient evidence to include other cancer types that are potentially associated with BRCA1 and BRCA2 in clinical management guidelines.ObjectiveTo evaluate the association of BRCA1 and BRCA2 pathogenic variants with additional cancer types and their clinical characteristics in 100 914 individuals across 14 cancer types.Design, setting, and participantsThis case-control analysis to identify cancer types and clinical characteristics associated with pathogenic variants in BRCA1 and BRCA2 included DNA samples and clinical information from 63 828 patients with 14 common cancer types and 37 086 controls that were sourced from a multi-institutional hospital-based registry, BioBank Japan, between April 2003 and March 2018. The data were analyzed between August 2019 and October 2021.Main outcomes and measuresGermline pathogenic variants in coding regions and 2 bp flanking intronic sequences in BRCA1 and BRCA2 were identified by a multiplex polymerase chain reaction-based target sequence method. Associations of (likely) pathogenic variants with each cancer type were assessed by comparing pathogenic variant carrier frequency between patients in each cancer type and controls.ResultsA total of 65 108 patients (mean [SD] age at diagnosis, 64.1 [11.6] years; 27 531 [42.3%] female) and 38 153 controls (mean [SD] age at registration, 61.8 [14.6] years; 17 911 [46.9%] female) were included in this study. A total of 315 unique pathogenic variants were identified. Pathogenic variants were associated with P < 1 × 10-4 with an odds ratio (OR) of greater than 4.0 in biliary tract cancer (OR, 17.4; 95% CI, 5.8-51.9) in BRCA1, esophageal cancer (OR, 5.6; 95% CI, 2.9-11.0) in BRCA2, and gastric cancer (OR, 5.2; 95% CI, 2.6-10.5) in BRCA1, and (OR, 4.7; 95% CI, 3.1-7.1) in BRCA2 in addition to the 4 established cancer types. We also observed an association with 2 and 4 other cancer types in BRCA1 and BRCA2, respectively. Biliary tract, female breast, ovarian, and prostate cancers showed enrichment of carrier patients according to the increased number of reported cancer types in relatives.Conclusions and relevanceThe results of this large-scale registry-based case-control study suggest that pathogenic variants in BRCA1 and BRCA2 were associated with the risk of 7 cancer types. These results indicate broader clinical relevance of BRCA1 and BRCA2 genetic testing.

Project description:BackgroundPatients with pathogenic sequence variants (PSVs) in BRCA1/BRCA2 are at high risk of developing ovarian cancer (OC). However, genetic testing for BRCA1/BRCA2 PSVs is still not a routine practice in the Middle East. With the lack of epidemiological studies in the region, we aim to describe the prevalence of BRCA1/BRCA2 PSVs in patients with OC across different countries in the Gulf region.MethodsThe PREDICT study was an observational, prospective, epidemiological study, which consecutively recruited women with ovarian, primary peritoneal, and fallopian tube cancers from the following Gulf countries over the period from July 2017 to July 2019; United Arab Emirates (UAE), Kuwait, and Oman. The study was approved by the local ethics committee of participating centers. The BRCA1/BRCA2 PSVs were assessed by tissue genetic testing using next-generation sequencing (NGS).ResultsA total of 105 women were included with a median age at diagnosis of 52 years (IQR 44.5 - 61.0). Nearly 11.4% of patients reported a family history of ovarian or breast cancer, while 4.7% of patients reported a family history of other cancers. Most of the patients (70.3%) had advanced disease (FIGO stage III/IV) at presentation. Eighty-eight patients (84%) were successfully tested for somatic BRCA1/BRCA2 PSVs. Fifteen patients (17%) were found to have PSVs in either BRCA1, BRCA2, or both genes; of them, 10 patients (11.2%) had BRCA1 somatic PSVs alone, eight patients (9.1%) had BRCA2 somatic PSVs, while three patients (2.9%) had both PSVs. Five patients with BRCA1/BRCA2 somatic PSVs had germline PSVs tests, and three of them tested positive. Concerning treatment, 87.6% of patients received perioperative chemotherapy and 6.6% as first-line palliative chemotherapy. Eighty-seven (82.9%) patients underwent debulking surgery, with no residual disease in 42.5% of patients.ConclusionOur study showed that the prevalence of BRCA1/BRCA2 somatic PSVs in patients with OC is higher than the reported global figures (2-8%). However, more studies are warranted to further elucidate the prevalence of BRCA1/BRCA2 somatic and germline PSVs, as well as other relevant genetic alterations, to better understand their impact on OC patient outcomes in Gulf countries.Trial registrationNCT03082976 .

Dataset Information

Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.

Publications

Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.

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