DNMT1 and breast cancer: We abolished DNMT1 and EZH2 expression by siRNA and found that knockdown either of the two genes alone induced the expression of miR-124-3p mRNA, and deletion of these two genes together had a more obvious induction in MDA-MB-231 (Fig. 5A), indicating that DNA methylation contributed to the downregulation of miR-124-3p in BC.