Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry
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Gabriela C. Fernandes1,*, Rodrigo A.D. Michelli2,*, Henrique C.R. Galvão2,*, André E. Paula1, Rui Pereira3,4, Carlos E. Andrade2, Paula S. Felicio5, Cristiano P. Souza2, Deise R.P. Mendes1, Sahlua Volc2, Gustavo N. Berardinelli1, Rebeca S. Grasel2, Cristina S. Sabato1, Danilo V. Viana2, José Carlos Machado4, José Luis Costa4, Edmundo C. Mauad2,6, Cristovam Scapulatempo-Neto1,5,7, Banu Arun8, Rui M. Reis1,2,5,9,10, Edenir I. Palmero1,2,5,11
1Center of Molecular Diagnosis, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
2Oncogenetics Department, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
3Institute of Research and Innovation in Health, University of Porto, Porto, Portugal
4Institute of Molecular Pathology and Immunology at the University of Porto (IPATIMUP), Porto, Portugal
5Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
6Prevention Department, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
7Pathology Department, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
8MD Anderson Cancer Center, Houston, Texas, USA
9Life and Health Sciences Research Institute (ICVS), Health Sciences School, University of Minho, Braga, Portugal
10ICVS/3B’s-PT Government Associate Laboratory, Braga/Guimarães, Portugal
11Barretos School of Health Sciences, Dr. Paulo Prata–FACISB, São Paulo, Brazil
*These authors contributed equally to this work
Edenir I. Palmero, email: [email protected]
Keywords: hereditary breast cancer, BRCA1/BRCA2 mutation profile in Brazil, genetic ancestry, HBOC in brazil, c.5266dupC prevalence in brazil
Received: April 04, 2016 Accepted: October 01, 2016 Published: October 12, 2016
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.
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