When ductal lavage was performed on asymptomatic BRCA1/2 mutation carriers, the cells within the lavage fluid of 8/19 women showed promoter hypermethylation of at least one of four genes (BRCA1, BRCA2, ERα, and RARβ2) that are often hypermethylated in breast cancer [56]. This evidence concerns the gene ESR1 and breast carcinoma.