Recurrent genetic alterations observed in adult primary GBM include mutations in PIK3CA and/or NF1, TERT promoter alterations, deletion of CDKN2A/B, mutation and/or deletion of PTEN, mutation and/or amplification of EGFR and PDGFRA, and overexpression of wildtype IDH1 [35,68,69,70,71]. The gene discussed is CDKN2A; the disease is glioblastoma.