IDH1 and glioblastoma: Notably, according to the fifth edition of the “Classification of Tumors of the Central Nervous System,” in IDH wild-type high-grade gliomas, H3K27M mutation and H3G34 mutation respectively define diffuse midline glioma, H3K27-altered glioma and diffuse hemispheric glioma, H3G34-mutant, which are no longer classified as IDH wild-type glioblastoma.90