The Relationship of Mutation Carriage of BRCA1/2 and Family History in Triple-Negative Breast Cancer: Experience from a Diagnostic Center in Turkey

Objective BRCA1/2 genes play a role in the etiopathogenesis of 10%-30% of triple-negative breast cancer (TNBC). This study aims to investigate the BRCA1/2 genes and the demographic and clinicopathological features in patients with TNBC. The study also examined the impact of cancer history of TNBC individuals' relatives on the risk of BRCA1/2 mutation carriership rate. Materials and Methods The BRCA1/2 genes of 65 women diagnosed with TNBC between 2011 and 2017 were investigated using next-generation sequencing. We analyzed the correlations of patients' demographic and clinicopathologic parameters and family history with BRCA1/2 mutation status. We used the χ2-test, t-test, Mann-Whitney U test, and logistic regression statistical methods. Results The BRCA1/2 mutation carrier rate was 16.9%. Patients who had BRCA1/2 mutations were compared with those who did not in terms of demographic and clinicopathological parameters. In the BRCA1/2 mutation carrier group, the Ki-67 index and the number of relatives with cancer were higher than the BRCA1/2 non-carrier group. Logistic regression analysis revealed that when the number of relatives with breast or ovarian cancer was ≥2, the risk of carrying the BRCA1/2 mutation increased by 15-fold. Regardless of the type of cancer (including cancers in other organs besides breast or ovary), the risk of carrying the BRCA1/2 mutation increased 1.3 times with each increase in the number of relatives with cancer for the patient with TNBC. Conclusion In cases with a diagnosis of TNBC, a significant relationship exists between the number of relatives with cancer in the family history and the risk of carrying mutations in the BRCA1/2 genes. This relationship can be confirmed further by large-scale studies with more cases.