G0S2 and glioblastoma: To test this hypothesis, we examined whether GBM cells transfected with a mutant IDH1 plasmid (pcDNA3-Flag-IDH1-R132H, a gift from Yue Xiong, #62907; Addgene, Cambridge, MA, USA) decreased the G0S2 mRNA level, and DNA hypomethylation by TET2 overexpression could restore the G0S2 mRNA level.