In tumor tissues, the promoter methylation levels of ESR2 correlated with those of APC, ABCB1 and ABCG2. In tumor-adjacent tissues, the methylation status correlated with that of MGMT. Rody et al. found the ESR2 promoter methylated in two-thirds of invasive breast cancers [72]. This evidence concerns the gene ABCB1 and invasive breast carcinoma.