IDH1 and intrahepatic cholangiocarcinoma: Compared to the trans-cancer type distributing pattern of Cluster1 mutations, IDH1/2, BAP1 mutations and FGFR2 fusions in Cluster2 were predominantly identified in ICC but rare in ECC or pancreatic ductal adenocarcinoma (PDAC), and our result revealed that all of the three genomic alterations tended to be mutually exclusive with Cluster1 mutations with extremely low overlapping frequencies.