IDH2 and glioblastoma: Transcriptome-based stratifications have produced three major isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) wild-type (wt) GBM subtypes, also called The Cancer Genome Atlas (TCGA) subtypes: proneural (PN), classical (CL), and mesenchymal (MS)2,10,11.