However, IDH1 mutations have been demonstrated to be subclonal in 20 % of GBMs [41], levels of amino acids, glutathione metabolites, choline derivatives, and TCA cycle intermediates were altered in mutant IDH1- and IDH2-expressing cells, and mutated IDH1-R132H enzyme can dominant-negatively inhibit IDH1-WT isocitrate dehydrogenase activity, meaning that the extent of metabolic heterogeneity may be influenced by the dominance of IDH1 mutations within the tumour hierarchy. This evidence concerns the gene IDH1 and neoplasm.