Deep sequencing studies have improved our understanding of the genomic complexity in iCCA and have identified the main targetable genetic alterations in the form of isocitrate dehydrogenase (IDH) and FGFR. Interestingly, the predominant genomic alterations in CCA are associated with epigenetic processes; 10–20% of iCCA tumors present mutations in IDH, with IDH1 and IDH2 being the ones of relevance in cancer, due to their involvement in cell metabolism [34]. The gene discussed is IDH1; the disease is cholangiocarcinoma.