IDH1 and hyperinsulinemic hypoglycemia, familial, 4: Increasingly, treatment decisions in advanced iCCA depend on the identification of actionable molecular alterations, including FGFR2 fusions or rearrangements, IDH1 mutations, HER2 amplifications, NTRK fusions, and microsatellite instability (MSI-high) and/or mismatch repair deficiency (dMMR).