Unsupervised clustering combined with Spearman correlation analysis of CpG site methylation and expression of PRSS3 transcripts in HCC cell lines revealed that among 17 CpGs distributed in the promoter region, methylation occurring at CpG sites 5-17 (-89~653 bp from the TSS of PRSS3-V1/V3) (Table S4) was inversely correlated with the mRNA expression level of PRSS3-V1, while methylation at CpG sites 12-16 (522 to 564 bp to PRSS3-V1 TSS) was highly related to PRSS3-V2 expression (Figure 3D and Figure S2, Table S5). The gene discussed is PRSS3; the disease is hepatocellular carcinoma.