CDKN2A and central nervous system cancer: 1. Risk stratification: This method is mainly used for refined prognostic stratification of IDH-mutant astrocytoma. Even with IDH mutation, if accompanied by CDKN2A/B homozygous deletion, the prognosis risk level significantly increases, which may affect the intensity of treatment strategies (such as more aggressive treatment or enrollment in clinical trials). GBM is mainly used for prognostic stratification of patients with an unmethylated MGMT promoter.2. Auxiliary diagnosis: Supports the diagnosis of high-grade gliomas.