IDH2 and central nervous system cancer: Oncologic patients with IDH1 and IDH2 mutant enzymes have a gain-of-function to further convert the α-ketoglutarate to 2HG, an oncometabolite which has been described as a useful oncomarker in the diagnosis and follow-up in glioma patients.38 The presence of 2HG can help to differentiate gliomas from non-neoplastic processes (e.g. demyelinating disease).