BRCA1 and breast cancer: Previously, we described that methylation of 11 genes (RARB, RASSF1, TWIST1, CCND2, ESSR1, SCGB3A1, BRCA1, BRCA2, CDKN2A, APC and CDH1) is involved in carcinogenesis of sporadic and BRCA1-associated breast cancer [9].