IDH2 and astrocytoma (excluding glioblastoma): The overall survival of patients with ASTRO PNC and IDH-mutant astrocytoma CNS WHO grade 4 patients showed no significant difference (p = 0.2446) but were significantly different to patients with IDH-mutant astrocytomas of CNS WHO grades 2 or 3 (p(A2) = < 0.0001; p(A3) = < 0.0001).