Gliomas harboring IDH mutations consequently display a CpG island methylator phenotype (G-CIMP), which is characterized by DNA hypermethylation in CpG-rich domains (Turcan et al., 2012) and has been shown to constitute a subset of tumors with a distinct biology and clinical behavior (Noushmehr et al., 2010). This evidence concerns the gene IDH2 and glioma.