IDH1 and astrocytoma (excluding glioblastoma): IDH1 mutation analysis was done on a population of 275 CNS WHO grade 4 adult-type diffuse gliomas with different IDH1 mutation status (i.e., 264 IDH1-wildtype glioblastomas vs. 11 IDH1-mutant astrocytomas) to investigate whether the proposed markers can characterize mutation status.