IDH1 and glioblastoma: All of the three tumors with IDH1/2 mutations had necrosis and microvascular proliferation, thus our cohort included four patients with GBM, IDH-wildtype, WHO grade 4 (57.1%) and three patients with astrocytoma, IDH-mutant, WHO grade 4 (42.9%) based on the WHO 2021 classification.