This study aimed to identify the levels of 5-hmC, 5-mC, TETl, TET2, TET3, IDH1, and IDH2 in tumor and the adjacent tissues, so as to explore whether the 5-hmC is decreased in HBV-related HCC tissues and, if possible, to explore the associated mechanism. The gene discussed is IDH2; the disease is hepatocellular carcinoma.