A study from Japan showed that 4.8% of perihilar cholangiocarcinoma also carry FGFR2 fusion, while the frequency of FGFR2 fusion in ICCA is 7.7% 52, which may be related to hilar and intrahepatic are not related to a clear anatomical classification, but this also shows the complexity of FGFR2 fusion mutations in CCA. This evidence concerns the gene FGFR2 and hilar cholangiocarcinoma.