In the absence of CDKN2A/B homozygous deletion, the widespread TP53 mutation in IDH-mutant astrocytoma is associated with shortened overall survival when compared with IDH-mutant astrocytoma of TP53-wildtype [24], a finding conforming to the importance of tumor-suppressor genes in cancer biology. This evidence concerns the gene CDKN2A and astrocytoma (excluding glioblastoma).