IDH1 and intrahepatic cholangiocarcinoma: Another example of genetic alterations in metabolic enzymes leading to accumulation of oncometabolites is the occurrence of activating oncogenic mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) producing the oncometabolite (D)-2-hydroxyglutarate (2HG), a phenomenon that has been identified in a variety of tumor types including acute myeloid leukemia (AML), glioma, chondrosarcoma, and intrahepatic cholangiocarcinoma, a deadly liver cancer [23-27].