CDKN2A and glioblastoma: CDKN2A is another important regulator of the TP53 pathway and the homozygous deletion of CDKN2A, which is prevalent in 22–35% of all GBMs (16–47% IDH-mutant GBM and ~58% of IDH-wildtype GBM), leads to inactivation of TP53 pathway and is associated with lower overall survival of GBM patients [65,73].