GSTP1 and hepatocellular carcinoma: 15 HCC-associated genes (p16, RASSF1A, APC, GSTP1, CDH1, p15, RUNX3, SOCS1, MGMT, SFRP1, PRDM2, DAPK1, p14, RARβ and p73) hypermethylation showed significant evidences between HCC tumor tissues and normal tissues to the risk of HCC.