IDH1 and glioblastoma: Homozygous losses of CDKN2A/B or RB1 were seen in subgroups of patients, with homozygous RB1 deletions being enriched in H3 G34-mutant diffuse hemispheric gliomas when compared to IDH-wildtype glioblastomas and IDH-mutant gliomas from the GGN cohort (reference cohort 3) (Supplementary Table S6).