Among the most valuable targets, isocitrate dehydrogenase‐1 (IDH1) mutations can be found in ~15%–20% of CCA, mostly in intrahepatic CCA (iCCA) [12, 13] and lead to hyperproduction of the oncometabolite 2‐hydroxyglutarate (2HG) [14, 15], resulting in epigenetic dysregulation, aberrant cell metabolism and promoting tumourigenesis [16]. The gene discussed is IDH1; the disease is cholangiocarcinoma.