Compared with a population-based cohort of patients with IDH-wildtype glioblastoma from the Canton of Zurich, Switzerland,27 that was re-classified according to the 2021 WHO classification (reference cohort 1, Note S1),1 patients with diffuse hemispheric glioma, H3 G34-mutant were younger (P < .001), had a higher Karnofsky performance status at diagnosis (P < .001), had a biopsy at diagnosis more often by trend (P = .067), and their tumors exhibited MGMT promoter methylation more often (P < .001). The gene discussed is IDH1; the disease is glioblastoma.