Epigenetic Inactivation of BRCA1 Through Promoter Hypermethylation and Its Clinical Importance in Triple-Negative Breast Cancer

BRCA1 promotor methylation was found only in TNBC cases and the methylated cases account for 16% of TNBC. BRCA1 promoter methylation was significantly associated with reduced BRCA1 expression, aggressive phenotype, and poor prognosis. BRCA1 promoter methylation is an important mechanism that leads to functional loss of BRCA1.