Interestingly, the results of blood DNA methylation levels of BRCA1, APC, RARB, ESR1, TIMP3, and GSTP1 were inconsistent among the previous studies, but a higher frequency of methylated DAPK in peripheral DNA was reported in BC cases compared to healthy controls in several studies (see Supplementary Table S4) [36,37,39,40]. This evidence concerns the gene GSTP1 and breast cancer.