IDH1 and cholangiocarcinoma: Studies have shown that upwards of 60% of cholangiocarcinoma (CCA) contain such aberrations, including those in isocitrate dehydrogenase-1 (IDH1), fibroblast growth factor receptor-2 (FGFR2), and neurotrophic tyrosine receptor kinase (NTRK) [15,16,17,18].