Objective To study the methylation of MGMT, DAPK, THBS1 and RIZ1 genes in hepatocellular carcinoma. MethodsMethylation specific PCR was adopted to investigate the promoter methylation of these genes in 40 cases of HCC and 2 normal liver tissues. The relationship between the frequency of methylation of the genes and clinical data was analyzed. ResultsNormal liver has no genes methylation. In patients with HCC, the frequency of methylation in MGMT, DAPK, THBS1 and RIZ1 was 15%, 77 5%, 37 5% and 30%, respectively. Methylation of at least one gene could be detected in 87 5% HCC patients. In the non tumor liver tissues, the frequency of methylation in MGMT, DAPK, THBS1 and RIZ1 were detected in 5%, 77 5%, 27 5% and 5%, respectively. Methylation of RIZ1 was more frequent in HCC than in non tumor liver tissues (? 2=8 658, P