2HG is accumulated in mutant IDH gliomas. A) Comparisons of amount of metabolites in mutant IDH and wild-type IDH gliomas show markedly higher accumulation of 2-HG (median 5.007 mM vs. 0.000 mM, Mann-Whitney test, p =0.0002) and lower concentrations of Glx (p <0.05) in mutant IDH gliomas. B) ROC curve analysis revealed an optimal cutoff of 1.489, with a sensitivity of 100.0% and specificity of 72.2%. 2HG was detectable in all mutant IDH gliomas, whereas in 10 out of 27 (37.0%) wild-type IDH gliomas, 2HG was not detectable (2HG =0) (p =0.0003, chi-squared test). Five out of 27 (10.3%) wild-type IDH gliomas yielded a 2-HG concentration higher than 1.489 mM.