IDH1 and glioma: As reviewed before, IDH mutations inhibit glioma stem cells’ differentiation by producing high levels of 2-hydroxyglutaric acid (2-HG), regulate vascular endothelial growth factor (VEGF) to promote the formation of the tumor microenvironment, and induce high levels of hypoxia-inducible factor-1α (HIF-1α) to promote glioma invasion [117].