Dataset Information

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry.

ABSTRACT:

Background

There are very few data about the mutational profile of families at-risk for hereditary breast and ovarian cancer (HBOC) from Latin America (LA) and especially from Brazil, the largest and most populated country in LA.

Results

Of the 349 probands analyzed, 21.5% were BRCA1/BRCA2 mutated, 65.3% at BRCA1 and 34.7% at BRCA2 gene. The mutation c.5266dupC (former 5382insC) was the most frequent alteration, representing 36.7% of the BRCA1 mutations and 24.0% of all mutations identified. Together with the BRCA1 c.3331_3334delCAAG mutation, these mutations constitutes about 35% of the identified mutations and more than 50% of the BRCA1 pathogenic mutations. Interestingly, six new mutations were identified. Additionally, 39 out of the 44 pathogenic mutations identified were not previously reported in the Brazilian population. Besides, 36 different variants of unknown significance (VUS) were identified. Regarding ancestry, average ancestry proportions were 70.6% European, 14.5% African, 8.0% Native American and 6.8% East Asian.

Materials and methods

This study characterized 349 Brazilian families at-risk for HBOC regarding their germline BRCA1/BRCA2 status and genetic ancestry.

Conclusions

This is the largest report of BRCA1/BRCA2 assessment in an at-risk HBOC Brazilian population. We identified 21.5% of patients harboring BRCA1/BRCA2 mutations and characterized the genetic ancestry of a sample group at-risk for hereditary breast cancer showing once again how admixed is the Brazilian population. No association was found between genetic ancestry and mutational status. The knowledge of the mutational profile in a population can contribute to the definition of more cost-effective strategies for the identification of HBOC families.

SUBMITTER: Fernandes GC

PROVIDER: S-EPMC5348334 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Publications

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry.

Fernandes Gabriela C GC Michelli Rodrigo A D RA Galvão Henrique C R HC Paula André E AE Pereira Rui R Andrade Carlos E CE Felicio Paula S PS Souza Cristiano P CP Mendes Deise R P DR Volc Sahlua S Berardinelli Gustavo N GN Grasel Rebeca S RS Sabato Cristina S CS Viana Danilo V DV Mauad Edmundo C EC Scapulatempo-Neto Cristovam C Arun Banu B Reis Rui M RM Palmero Edenir I EI

Oncotarget 20161201 49

<h4>Background</h4>There are very few data about the mutational profile of families at-risk for hereditary breast and ovarian cancer (HBOC) from Latin America (LA) and especially from Brazil, the largest and most populated country in LA.<h4>Results</h4>Of the 349 probands analyzed, 21.5% were BRCA1/BRCA2 mutated, 65.3% at BRCA1 and 34.7% at BRCA2 gene. The mutation c.5266dupC (former 5382insC) was the most frequent alteration, representing 36.7% of the BRCA1 mutations and 24.0% of all mutations ...[more]

PMID: 27741520

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Project description:BackgroundBreast cancer is the most common cancer among women worldwide. Here, we report the prevalence of BRCA1/2 mutations in patients with high-risk breast cancer from Inner Mongolia and Jilin, China, which was a part of a nationwide project on the detection of BRCA1/2 mutations in Chinese patients with hereditary breast cancer.MethodsAccording to the criteria, index patients from a total of 245 independent families were initially recruited. All 49 exons of BRCA1 and BRCA2 and adjacent noncoding regions were screened for mutations based on next-generation sequencing from collected saliva.ResultsWe detected 17 BRCA1/2 variants in 18 of 216 (8.3%) index patients with high-risk breast cancer. Among these, seven mutations were novel, including four BRCA1 mutations (c.123_124delCAinsAT, c.5093_5096delCTAA, c.5396-2A>G, and c.2054delinsGAAGAGTAACAAGTAAGAAGAGTAACAAGAAG), and three BRCA2 mutations (c.304A>T, c.7552_7553insT, and c.9548_9549insA). The BRCA1/2 variants were identified in 14% (8/57) of the patients with triple-negative breast cancer and in 6.3% (10/159) of the patients with non-triple-negative breast cancer. There was no significant difference between the two groups (p = 0.07). A higher frequency for BRCA1 mutations was observed in patients with triple-negative breast cancer than in those with non-triple-negative breast cancer (12.3% vs. 2.5%, p = 0.004). The frequencies of the BRCA2 mutations were not significantly different between patients with triple-negative breast cancer and those with non-triple-negative breast cancer (1.8% vs. 3.8%, p = 0.46).ConclusionWe found that patients with triple-negative breast cancer had a higher frequency of BRCA1 mutations than those with non-triple-negative breast cancer. In this study, no significant associations between the BRCA1/2 mutation status and age, family history of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer, number of primary lesions, tumor size, or lymph node metastasis were observed.

Dataset Information

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry.

Background

Results

Materials and methods

Conclusions

Publications

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry.

Similar Datasets

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