While our analysis did not explicitly identify 1p and 19q deletions as strongly associated with better prognosis (ranks 45, 233), it did identify CIC mutations, a signature of oligodendrogliomas (CIC mutations occur in more than 50% of oligodendrogliomas), and SMARCA4 mutations, that occur frequently in both the less aggressive oligodendroglioma and IDH-mutant astrocytoma subtypes. This evidence concerns the gene IDH1 and astrocytoma (excluding glioblastoma).