SFRP1 and hepatocellular carcinoma: In the present study, we analysed the promoter hypermethylation status of the human p16, MGMT, GSTP1, DAP-kinase, APC, RIZ1, SFRP1, SFRP2, SFRP5, RUNX3, and SOCS1 genes in the multiple tumour DNA and the corresponding normal DNA of HCC, and tried to apply it to determine their clonality.