IDH1 and glioblastoma: According to the WHO CNS 2021 classification, the term glioblastoma is assigned only to the IDH wild-type subclass, fulfilling the specific histopathological characteristics of diffuse astrocytoma but with one or more genetic modifications (Telomerase reverse transcriptase-TERT promoter mutation, chromosome 7 or chromosome 10 damage (+7/−10), or Epidermal Growth Factor Receptor-EGFR gene amplification).