SFRP1 and hepatocellular carcinoma: To assess whether the down-regulation of SFRP1 could contribute to hepatocarcinogenesis, plasmid pcDNA3.0 with full ORF of SFRP1 under the control of the SV40 promoter were first transiently transfected into YY-8103, a HCC cell line, without the significant expression of endogenetic SFRP1 (Fig. 1E), where the empty vector pcDNA3.0 was used as control (Fig. 2A).