IDH1 and neoplasm: Nakamura et al. emphasized the difference in anatomical location of the tumour, highlighting IDH, EPHA2 and BAP1 mutations and FGFR2 fusions in iCCA, whereas extrahepatic tumours specifically show PRKACA and PRKACB fusions as well as mutations in ELF3 (similar to tumours in the ampulla of Vater)127 and ARID1B56.