Prevalence of BRCA1 and BRCA2 genes promoter hypermethylation in breast cancer tissue

Abstract

Recent advances in the treatment of breast cancer (BC) have been related to the personalization of therapy. The methylation status of the promoter regions of tumor suppressor genes such as BRCA1 and BRCA2 is supposed to be useful as a prognostic factor in BC patients. Aim: To investigate the frequency of hypermethylation in the promoter regions of BRCA1 and BRCA2 genes in tumor tissue of BC patients, and the relation of hypermethylation to the clinical course of the disease. Materials and Methods: Molecular genetic studies were performed on 50 BC tissue samples in order to determine the methylation status of the promoter regions of the BRCA1 and BRCA2 genes. Results: Hypermethylation of the BRCA1 promoter region was detected in 34% of BC cases, hypermethylation of the BRCA2 promoter region — in 50% of cases, and hypermethylation of the promoter region of both genes — in 20% of cases. A significant increase in the incidence of hypermethylation of the BRCA2 promoter region was found in the group of patients older than 56 years, mainly in patients with triple-negative breast cancer and without family history of BC. Conclusions: The high frequency of hypermethylation in the promoter regions of BRCA1 and BRCA2 genes, as well as their co-methylation in tumor tissue of BC patients has been detected.