Therefore, the aims of this study are as follows: to confirm the association between LINE-1 methylation levels and prognosis in HCC by using a greater number of samples; to examine prognostic significance in ICC and cHCC-CC; to analyze the difference in the characteristics of LINE-1 methylation levels among the various subtypes of PLC (i.e., HCC, ICC, cHCC-CC). Here, HSPG2 is linked to cholangiocarcinoma.