CDKN2A and astrocytoma (excluding glioblastoma): Among patients with CNS WHO grade 4 astrocytoma, median overall survival was 5.5 years (95% CI 4.3–6.7) without (n = 58) versus 1.8 years (95% CI 0–4.1) with (n = 12) homozygous CDKN2A deletion.