TP53 and astrocytoma (excluding glioblastoma): Previous studies have suggested that oligoastrocytomas (OAs) showed genetic subsets characterized by either oligodendroglioma-like alterations (1p and/or 19q loss, 52% and 70% of OAs), or astrocytoma-like alterations (TP53 mutations, 32%).27 Other studies have indicated gliomas previously characterized as OAs contain subsets driven by mutations to the TERT promoter region.28 Given that OAs are no longer a recognized diagnostic entity, identifying the molecular subpopulations that exist can inform the practical reclassification of this group.