IDH1 and central nervous system cancer: Since the discovery of a somatic IDH1 mutation in colorectal cancer patients [3], other mutations of IDH1 and IDH2 have been identified in many other cancers such as secondary glioblastoma and glioma [4, 5, 6] (~ 80%), chondrosarcoma (50–80%) [5, 7], thyroid carcinoma (16%) [5, 8] intrahepatic cholangiocarcinoma (10–20%) [5, 9], and in other types of solid tumors at lower frequencies [5, 10, 11].