A previous study demonstrated that IDH1 mutations result in the production of the onco-metabolite 2-hydroxyglutarate, and indicated that the excess 2-hydroxyglutarate contributes to the formation and malignant progression of ICC [27], gliomas [28], and chronic myelogenous leukaemia [29]. This evidence concerns the gene IDH1 and intrahepatic cholangiocarcinoma.