TP53 and glioblastoma: Similarly, in IDH1-mutated T98G glioblastoma cells, PICPG-4 glioma cells (IDH1-R132H + , PDGF + , TP53−/−; derived from a transgenic mouse model) and isogenic HCT116 IDH1-R132H cells treatment with ABT263 resulted in an enhanced fraction of subG1 cells (apoptotic cells) when compared to T98G IDH1-WT, PPC2 (IDH1-WT) or HCT116 IDH1-WT cells (Fig. 1f and Supplementary Fig. 2A, B).