Consequently, “Glioblastoma, IDH-wildtype” in adults should be diagnosed in the setting of an IDH-wildtype diffuse and astrocytic glioma if there is either microvascular proliferation, or necrosis, or TERT promoter mutation, or EGFR gene amplification, or +7/−10 chromosome copy number changes. The gene discussed is IDH1; the disease is glioblastoma.