IDH2 and glioblastoma: Recent single-cell analysis of the intratumoral heterogeneity of IDH-wild-type tumors recently led to a new model of four cellular states in glioblastoma: (i) oligodendrocyte-progenitor-like (OPC-like), (ii) neural-progenitor-like (NPC-like), (iii) astrocyte-like (AC-like), and (iv) mesenchymal-like (MES-like) states.