IDH1 and intrahepatic cholangiocarcinoma: More recently, other larger studies have demonstrated that the most frequent genetic alterations in ICC occur to be in TP53 (TP53; 27%), cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B; 27%), KRAS (22%), AT-rich interactive domain-containing protein 1A (ARID1A; 18%), and isocitrate dehydrogenase 1/2 (IDH1; 20%), BRCA1 associated protein (BAP1, 15%), FGFR2 (11%), and MET (2%) genes [42].