In HBV-associated HCC, Zhong et al. reported the common hypermethylation of GSTP1 gene and low protein expression, and the DNA methyltransferase inhibitor 5-aza-deoxycytidine reversed the hypermethylation of GSTP1 in Hep3B and HepG2 cell lines [66]. Here, GSTP1 is linked to hepatocellular carcinoma.