Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.
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ABSTRACT:
SUBMITTER: Li J
PROVIDER: S-EPMC6320715 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Accurate interpretation of BRCA1/2 variants is critical for risk assessment and precise treatment of breast cancer (BC). Hence, the establishment of an ethnicity-based BRCA1/2 variant database of the Chinese population is of paramount importance. In this study, panel-based sequencing served to detect BRCA1/2 variants in a Chinese multicenter cohort of 21,216 BC patients and 6434 healthy controls. Overall, the percentage of subjects carrying pathogenic variants was 5.5% (1174/21,216) in BC patients and 1.1% (71/6434) in healthy controls. We identified 13 pathogenic variants as high-frequency variants that had a frequency of > 0.45‰ in BC patients (≥ 10 in 21,216 patients), none of which has been reported in Caucasians. Pathogenic BRCA1/2 variants correlated with younger onset age, higher frequencies of bilateral and triple-negative BC (TNBC), invasive carcinomas, high histological grades, and family history of BC and other cancers. Furthermore, the percentage of the subjects carrying VUS was 9.8% (2071/21,216) in BC patients and 6.9% (446/6434) in healthy controls. Based on our cohort study, we unambiguously reclassified 7 out of the 858 VUS resulting in lower VUS ratio in patients (from 9.8 to 7.9%) as well as in healthy control (from 6.9 to 5.3%). We also re-analyzed the 100 variants in 13 exons (2-5 and 15-23) of the BRCA1 genes using a functional assay (saturation genome editing; SGE). 55 of the 59 VUS had distinct status in the SGE study: 24 (43.6%) were pathogenic, and 31 (56.4%) were benign. Strong ethnicity-specific occurrences of pathogenic BRCA1/2 variants were identified in the Chinese population. Hence, the findings provide rationale and sequencing information for the implementation of BRCA1/2 variants tailored to the Chinese population into clinical risk assessment.
| S-EPMC7814423 | biostudies-literature
Project description:BackgroundA mutation found in the BRCA1 or BRCA2 gene of a breast tumor could be either germline or somatically acquired. The prevalence of somatic BRCA1/2 mutations and the ratio between somatic and germline BRCA1/2 mutations in unselected breast cancer patients are currently unclear.Patients and methodsPaired normal and tumor DNA was analyzed for BRCA1/2 mutations by massively parallel sequencing in an unselected cohort of 273 breast cancer patients from south Sweden.ResultsDeleterious germline mutations in BRCA1 (n = 10) or BRCA2 (n = 10) were detected in 20 patients (7%). Deleterious somatic mutations in BRCA1 (n = 4) or BRCA2 (n = 5) were detected in 9 patients (3%). Accordingly, about 1 in 9 breast carcinomas (11%) in our cohort harbor a BRCA1/2 mutation. For each gene, the tumor phenotypes were very similar regardless of the mutation being germline or somatically acquired, whereas the tumor phenotypes differed significantly between wild-type and mutated cases. For age at diagnosis, the patients with somatic BRCA1/2 mutations resembled the wild-type patients (median age at diagnosis, germline BRCA1: 41.5 years; germline BRCA2: 49.5 years; somatic BRCA1/2: 65 years; wild-type BRCA1/2: 62.5 years).ConclusionsIn a population without strong germline founder mutations, the likelihood of a BRCA1/2 mutation found in a breast carcinoma being somatic was ∼1/3 and germline 2/3. This may have implications for treatment and genetic counseling.
| S-EPMC4959927 | biostudies-literature
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.
| S-EPMC4892623 | biostudies-literature
Project description:Inherited germline pathogenic variants are responsible for ~5% of breast cancer globally. Through rapid expansion and isolation since immigration in the early 17th century, French Canadians are a relatively genetically homogenous founder population and therefore represent a unique demographic for genetic contributions to disease. To date, twenty variants in BRCA1, BRCA2, and PALB2 that predispose families to breast and ovarian cancer have been identified as recurring in the French-Canadian founder population. Our objective was to evaluate the clinical efficacy and validity of targeted genetic testing for these variants in Montreal French Canadians. A total of 555 breast cancer cases unselected for family history or age of diagnosis were genotyped, along with 1940 controls without a personal or family history of cancer. A Sequenom genotyping assay identified a pathogenic variant in 0.2% (5 of 1940) of cancer-free controls, and 3.8% (21/555) of breast cancer cases. Almost 10% (12/113) of early onset cases were heterozygous for founder BRCA1 or BRCA2 pathogenic variant. Of twenty variants tested, only seven were identified in this study. The option of providing this test as population-based screening is discussed.
| S-EPMC7162921 | biostudies-literature
Project description:The contribution of germline copy number variants (CNVs) to risk of developing cancer in individuals with pathogenic BRCA1 or BRCA2 variants remains relatively unknown. We conducted the largest genome-wide analysis of CNVs in 15,342 BRCA1 and 10,740 BRCA2 pathogenic variant carriers. We used these results to prioritise a candidate breast cancer risk-modifier gene for laboratory analysis and biological validation. Notably, the HR for deletions in BRCA1 suggested an elevated breast cancer risk estimate (hazard ratio (HR) = 1.21), 95% confidence interval (95% CI = 1.09-1.35) compared with non-CNV pathogenic variants. In contrast, deletions overlapping SULT1A1 suggested a decreased breast cancer risk (HR = 0.73, 95% CI 0.59-0.91) in BRCA1 pathogenic variant carriers. Functional analyses of SULT1A1 showed that reduced mRNA expression in pathogenic BRCA1 variant cells was associated with reduced cellular proliferation and reduced DNA damage after treatment with DNA damaging agents. These data provide evidence that deleterious variants in BRCA1 plus SULT1A1 deletions contribute to variable breast cancer risk in BRCA1 carriers.
| S-EPMC9537519 | biostudies-literature
Project description:Hereditary breast cancer is known for its strong tendency of inheritance. Most hereditary breast cancers are related to BRCA1/BRCA2 pathogenic variants. The lifelong risk of breast cancer in pathogenic BRCA1 and BRCA2 variant carriers is approximately 65% and 45%, respectively, whereas that of ovarian cancer is estimated to be 39% and 11%, respectively. Therefore, understanding these variants and clinical knowledge on their occurrence in breast cancers and carriers are important. BRCA1 pathogenic variant breast cancer shows more aggressive clinicopathological features than the BRCA2 pathogenic variant breast cancer. Compared with sporadic breast cancer, their prognosis is still debated. Treatments of BRCA1/BRCA2 pathogenic variant breast cancer are similar to those for BRCA-negative breast cancer, mainly including surgery, radiotherapy, and chemotherapy. Recently, various clinical trials have investigated poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitor treatment for advanced-stage BRCA1/BRCA2 pathogenic variant breast cancer. Among the various PARP inhibitors, olaparib and talazoparib, which reached phase III clinical trials, showed improvement of median progression-free survival around three months. Preventive and surveillance strategies for BRCA pathogenic variant breast cancer to reduce cancer recurrence and improve treatment outcomes have recently received increasing attention. In this review, we provide an information on the clinical features of BRCA1/BRCA2 pathogenic variant breast cancer and clinical recommendations for BRCA pathogenic variant carriers, with a focus on treatment and prevention strategies. With this knowledge, clinicians could manage the BRCA1/BRCA2 pathogenic variant breast cancer patients more effectively.
| S-EPMC6822003 | biostudies-literature
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.
| S-EPMC9011177 | biostudies-literature
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 .
| S-EPMC8690897 | biostudies-literature
Project description:PurposeWe assessed the associations between population-based polygenic risk scores (PRS) for breast (BC) or epithelial ovarian cancer (EOC) with cancer risks for BRCA1 and BRCA2 pathogenic variant carriers.MethodsRetrospective cohort data on 18,935 BRCA1 and 12,339 BRCA2 female pathogenic variant carriers of European ancestry were available. Three versions of a 313 single-nucleotide polymorphism (SNP) BC PRS were evaluated based on whether they predict overall, estrogen receptor (ER)-negative, or ER-positive BC, and two PRS for overall or high-grade serous EOC. Associations were validated in a prospective cohort.ResultsThe ER-negative PRS showed the strongest association with BC risk for BRCA1 carriers (hazard ratio [HR] per standard deviation = 1.29 [95% CI 1.25-1.33], P = 3×10-72). For BRCA2, the strongest association was with overall BC PRS (HR = 1.31 [95% CI 1.27-1.36], P = 7×10-50). HR estimates decreased significantly with age and there was evidence for differences in associations by predicted variant effects on protein expression. The HR estimates were smaller than general population estimates. The high-grade serous PRS yielded the strongest associations with EOC risk for BRCA1 (HR = 1.32 [95% CI 1.25-1.40], P = 3×10-22) and BRCA2 (HR = 1.44 [95% CI 1.30-1.60], P = 4×10-12) carriers. The associations in the prospective cohort were similar.ConclusionPopulation-based PRS are strongly associated with BC and EOC risks for BRCA1/2 carriers and predict substantial absolute risk differences for women at PRS distribution extremes.
| S-EPMC7521995 | biostudies-literature
Project description:BACKGROUND:An association between BRCA pathogenic variants and an increased endometrial cancer risk, specifically serous-like endometrial cancer, has been postulated but remains unproven, particularly for BRCA2 carriers. Mechanistic evidence is lacking, and any link may be related to tamoxifen exposure or testing bias. Hysterectomy during risk-reducing bilateral salpingo-oophorectomy is, therefore, of uncertain benefit. Data from a large, prospective cohort will be informative. METHODS:Data on UK BRCA pathogenic variant carriers were interrogated for endometrial cancer diagnoses. Standardised incidence ratios (SIRs) were calculated in four distinct cohorts using national endometrial cancer rates; either from 1/1/1980 or age 20, prospectively from date of personal pathogenic variant report, date of family pathogenic variant report or date of risk-reducing salpingo-oophorectomy. Somatic BRCA sequencing of 15 serous endometrial cancers was performed to detect pathogenic variants. RESULTS:Fourteen cases of endometrial cancer were identified in 2609 women (1350 BRCA1 and 1259 BRCA2), of which two were prospectively diagnosed. No significant increase in either overall or serous-like endometrial cancer risk was identified in any of the cohorts examined (SIR = 1.70, 95% confidence interval = 0.74-3.33; no cases of serous endometrial cancer diagnosed). Results were unaffected by the BRCA gene affected, previous breast cancer or tamoxifen use. No BRCA pathogenic variants were detected in any of the serous endometrial cancers tested. CONCLUSIONS:Women with a BRCA pathogenic variant do not appear to have a significant increased risk of all-type or serous-like endometrial cancer compared with the general population. These data provide some reassurance that hysterectomy is unlikely to be of significant benefit if performed solely as a preventive measure.
| S-EPMC7441309 | biostudies-literature