To examine whether DNA methylation at the IGF2 intron 3 region, and at the IGF2, H19 and PEG1/MEST DMRs may mediate the association between HPV infection and ICC, we ran mixed models—to allow for unconstrained model entry of individual CpGs at each DMR—to evaluate associations between DNA methylation levels at each of these four DMRs and HPV infection, in which no HPV infection served as the baseline category (Table 3). Here, IGF2 is linked to intrahepatic cholangiocarcinoma.