Hypermethylation in BC includes genes encoding for BRCA1 protein [8], TIMP metallopeptidase inhibitor 3 (TIMP3) [9], Ras association domain family 1 isoform A (RASSF1A) [10], retinoic acid receptor β (RARβ) [11], and estrogen receptor-alpha (ERα) [12], among others. This evidence concerns the gene ESR1 and breast cancer.