In support of the results of in vitro enzymatic analyzes, d-2HG levels are 100-fold higher in cases of glioma and AML that carry IDH1 or IDH2 mutations as compared with tumors with wild type IDH (Dang et al., 2009; Gross et al., 2010; Ward et al., 2010; Andersson et al., 2011). The gene discussed is IDH2; the disease is central nervous system cancer.