Furthermore, in HBV-associated HCC, the intensive hypermethylation of the CpG island of the tumor suppressor gene RASSF1A may be pathologically important in this tumor type, based on studies of human HBV-associated HCC tissues and HCC cell lines (Hep3B, HepG2, SK-HEP-1 and Huh-7) (29). This evidence concerns the gene RASSF1 and hepatocellular carcinoma.