CDKN2A and glioblastoma: Several genes in the central glioblastoma pathways were identified through dramatic copy number alterations, such as amplification of the oncogenes, EGFR, c-MYC, CDK4, PDGFRA, MDM2, and MDM4, and deletion of the tumor suppressor genes, CDKN2A, CDKN2B, and PTEN [5-9].