Detectable in-Blood Brca1 Methylation as a Biomarker of Breast Cancer Predisposition

Germline BRCA1 mutations are a well-established risk factor for the development of breast cancer. Nevertheless, many patients who present with a clinical phenotype typical of BRCA1-associated tumors do not carry pathogenic BRCA1 mutations. Current risk models are inadequate, highlighting the need for new biomarkers. In this context, blood-based epigenetic markers such as DNA methylation are being explored. Many studies have examined BRCA1 promoter methylation in blood DNA as a BC risk marker. Retrospective analyses report that BRCA1 methylation in blood correlates with higher risk in triple-negative tumors. However, findings remain inconsistent due to numerous technical issues, including methodological variability, assay limitations, and differences in targeted CpG sites. This review highlights the risk of developing breast cancer in women with a methylated BRCA1 promoter in peripheral blood-derived DNA, as well as the potential drawbacks and challenges in this area. Methodology: Relevant studies were identified through a targeted search of the PubMed database using keywords such as “BRCA1,” “methylation,” “breast cancer,” and “blood DNA.” Inclusion criteria comprised studies evaluating BRCA1 promoter methylation in blood-derived DNA in relation to breast cancer risk. Studies analyzing BRCA1 promoter methylation exclusively in tumor tissue or other non-blood specimens were excluded.