Consistent with our hypothesis, re-expression of MPPED2 was obtained in MDA-MB-231 (*, p < 0.05) and SKBR3 (**, p < 0.01) cells after 5-Aza-dC treatment (Figure 3F,G), confirming that the downregulation of MPPED2 expression in BC could be mainly due to the hypermethylation of MPPED2 regulatory regions. The gene discussed is MPPED2; the disease is breast cancer.