It has been suggested that infection with hepatitis B virus (HBV) or hepatitis C virus (HCV) increases the aberrant methylation of tumor suppressor genes in HCC, including the GSTP1 gene [8], [9], [10], [13], [15], [43], in HBV-infected HCC but not in non-HBV-infected HCC or in non-HCV-infected HCC. The gene discussed is GSTP1; the disease is hepatocellular carcinoma.