However, patients with intrahepatic cholangiocarcinoma harbor frequent genetic alterations such as isocitrate dehydrogenase (IDH)-1 (20.6–29.1%) and -2 (2.5–4.4%) mutations and fibroblast growth factor receptor 2 (FGFR2) fusions (10–15%), which can be treated with IDH1/2 or FGFR2 inhibitors (55, 56). Here, IDH1 is linked to intrahepatic cholangiocarcinoma.