Remarkably, α-KG levels are unchanged in mutant IDH AML and glioma (Dang et al., 2009; Gross et al., 2010), and it is now clear that 2-HG-mediated inhibition of 2-OG-dependent dioxygenases is the dominant mechanism by which IDH mutations are oncogenic (Xu et al., 2011). This evidence concerns the gene IDH1 and central nervous system cancer.