IDH1 and diffuse astrocytoma: Among 209 IDH-wildtype diffuse gliomas (146 GBM, 38 anaplastic astrocytomas, and 25 diffuse astrocytomas) according to the WHO CNS4 classification, 191 (91%) were reclassified as GBM (146 hist-GBMs and 45 mol-GBMs), 11 (5%) as H3-wildtype and IDH-wildtype pediatric-type high-grade diffuse gliomas, and 7 (3%) as MYB/MYBL1-altered pediatric-type low-grade diffuse astrocytomas based on the WHO CNS5 classification system (Figure 1).