IDH1 and glioma: Comparison of H3K27M-Mut glioma and IDH-Mut glioma reveal a higher fraction of non-proliferating OC-like cells in H3K27M-Mut glioma.34 These findings strongly imply that H3K27M histone mutations specifically induce a differentiation block along the OPC-OC axis and maintain a source of OPC-like progenitors to repopulate the tumor.34 Importantly, this work ascribes a unique functional role of OPCs to the maintenance of H3K27M-Mut gliomas.