DNA hypermethylation of SFRP1 promoter in primary HCC samples. (A) Transcriptional expression of SFRP1 was analyzed by RT-PCR in two pairs of HCCs and corresponding non-cancerous livers, where β-actin was used as an internal control. (B) The bisulfite-treated DNA sequencing was preformed on the genomic region (-160 ~ + 200) around TSS of SFRP1, where the extent of methylation of the promoter was evaluated through DNA sequencing on 8 random clones inserted by PCR products. There were 56 CpG dinucleotides (CpGs), represented by circles, located on the region. Black and white circles represented the methylated and unmethylated CpG dinucleotides, respectively, where the methylation status was determined by bisulfite-treated DNA sequencing on the corresponding clones. C, HCCs; N, non-cancerous livers.