ICC of C class harbors recurrent focal CNAs including deletions involving CDKN2A, ROBO1, ROBO2, RUNX3, and SMAD4, while those of M class harbor recurrent mutations in the genes frequently mutated in ICC, i.e., TP53, KRAS, and IDH1, as well as epigenetic regulators and genes in TGFβ signaling pathway. Here, IDH1 is linked to intrahepatic cholangiocarcinoma.