CDKN2A and glioblastoma: Epidermal growth factor receptor (EGFR) overexpression, PTEN (MMAC I) mutation, CDKN2A (p16) deletion, and less frequently MDM2 amplification are just a few defects which lead to uncontrolled proliferation, invasion, and angiogenesis in primary glioblastoma (GBM) [3].