RB1 and glioblastoma: Verhaak et al. [13], proposed the GBM subtype classification by evaluating transcriptome profiles with a system-based approach: Proneural (high PDGFRA gene expression and frequent IDH1 mutation), neural (defects on SYT1, SLC12A5, GABRA1, and NEFL), classical (chr.7 amplification, chr.10 loss, RB inactivation, and NES overexpression), and mesenchymal (P53, PTEN, and NF1, overexpression in NF-κB pathway).