Analysis of the pathogenic variants of BRCA1 and BRCA2 using next-generation sequencing in women with familial breast cancer: a case-control study

Abstract

Background: Pathogenic variants (PVs) of BRCA genes entail a lifetime risk of developing breast cancer in 50-85% of carriers. Their prevalence in different populations has been previously reported. However, there is scarce information regarding the most common PVs of these genes in Latin-Americans. This study identified BRCA1 and BRCA2 PV frequency in a high-risk female population from Northeastern Mexico and determined the association of these mutations with the patients' clinical and pathological characteristics.

Methods: Women were divided into three groups: aged ≤ 40 years at diagnosis and/or risk factors for hereditary breast cancer (n = 101), aged > 50 years with sporadic breast cancer (n = 22), and healthy women (n = 72). Their DNA was obtained from peripheral blood samples and the variants were examined by next-generation sequencing with Ion AmpliSeq BRCA1 and BRCA2 Panel using next-generation sequencing.

Results: PVs were detected in 13.8% group 1 patients (BRCA1, 12 patients; BRCA2, 2 patients). Only two patients in group 2 and none in group 3 exhibited BRCA1 PVs. Variants of uncertain significance were reported in 15.8% patients (n = 16). In group 1, patients with the triple-negative subtype, PV frequency was 40% (12/30). Breast cancer prevalence in young women examined in this study was higher than that reported by the National Cancer Institute Surveillance, Epidemiology (15.5% vs. 5.5%, respectively).

Conclusions: The detected BRCA1 and BRCA2 PV frequency was similar to that reported in other populations. Our results indicate that clinical data should be evaluated before genetic testing and highly recommend genetic testing in patients with the triple-negative subtype and other clinical aspects.

Keywords: BRCA1 and BRCA2 genes; Breast cancer; Hereditary; Pathogenic variant; Triple-negative subtype.