Whereas in iCC alterations in genes dedicated as ESCAT I/II (FGFR2 fusion, BRAF-V600E mut., Her2neu amplification, IDH1 mut., MSI and NTRK Fusion) according to the latest ESMO guidelines for molecular testing in biliary tract cancer were more frequent than in eCC (27.5% vs. 10.5%; p = 0.0093) (Fig. 2A,B; Supplementary Table). The gene discussed is IDH1; the disease is biliary tract cancer.