A study of >200 cholangiocarcinomas has revealed marked differences in the mutational patterns between cancers caused by Opisthorchis viverrini infection and those without infectious aetiologies. Namely, BAP1, IDH1 and IDH2 mutations were more common in noninfectious cancers, whereas TP53 mutations were common within the O. viverrini-related cancers. These results show how certain environmental exposures can dramatically change the somatic mutational landscape of this common hepatic cancer.