IntroductionEpigenetic alterations, in particular DNA methylation, are the most important mechanism that silences tumor suppressor genes during carcinogenesis. Methylation of the BRCA1 promoter in peripheral blood is associated with an increased risk of breast cancer. In the present study, we aimed, for the first time in western Algeria, to investigate the role of BRCA1 CpG promoter methylation in peripheral blood cells (PBCs) among breast cancer patients, as a potential biomarker for detecting breast cancer risk at an early age.Material and methodsThe methylation profile of the BRCA1 gene promoter and its frequency in PBCs, derived from 39 breast cancer patients, was explored by methylation-specific PCR (MSPCR). The association between methylation profiles and clinicopathological features was evaluated with SPSS statistics software to estimate a convenient biomarker for early detection of breast cancer.ResultsMSPCR results demonstrated that the methylation frequency of the BRCA1 gene promoter detected in PBCs is significantly higher than in other populations. It was observed in 23 of 39 (58.97%) breast cancer patients.ConclusionsOur study showed that the methylation of the BRCA1 gene promoter detected in PBCs’ DNA could have potential utility in clinical diagnostics as a new biomarker for breast cancer risk in Algerian women and for early detection.