IGF2 and intrahepatic cholangiocarcinoma: When compared with controls, a 10 % decrease in methylation at the IGF2 intron 3 region (methylation mean = 71.97, SD = 8.5) was associated with a two-fold increase in ICC risk (OR 2.00, 95 % CI 1.14–3.44), after adjusting for age, gravidity, HIV-1 status, HPV infection, and oral contraceptive use.