CDK4 and glioblastoma: TCGA analyses of GBM have identified several critical genetic aberrations, including mutations in TP53, PTEN, NF1, EGFR, RB1, PIK3R1, IDH1, PIK3CA, SPTA1, ATRX, KEL, GABRA6, LZTR1, CTNND2, BRAF, amplifications of EGFR, CDK4, PDGFRA, MDM2, MET, MDM4, CDK6, MYCN, CCND2, PIK3CA, AKT3, and deletions of CDKN2A, CDKN2B, PTEN, CDKN2C, RB1, PARK2 and NF1 [19, 42].