Various small studies have demonstrated a link between HCV and ICC. A recent large cohort study of >140,000 HCV-infected military veterans showed a >2-fold increase in ICC risk in HCV-infected patients versus noninfected controls. However, many of these hospital-based, case-control studies are limited by the potential for selection or ascertainment bias, and some studies have failed to observe any association between HCV and ICC.The association of HCV infection with susceptibility to ICC, and the pathogenetic basis for such an association, warrant further investigation. Chronic HCV infection was not a risk for extrahepatic cholangiocarcinoma (ECC).