Grade 4 IDH1/2-mutant astrocytomas with intact CDKN2A/B and focal amplifications showed decreased median survival at 55.9 months while grade 4 tumors with loss of CDKN2A/B (hemizygous: 31.9 months, homozygous: 32.5 months) fared the worst. This evidence concerns the gene IDH1 and astrocytoma (excluding glioblastoma).