Genome sequencing studies of GBM have illuminated biologically relevant alterations in three core pathways, namely MDM2/p53, Rb/E2F, and receptor tyrosine kinase (RTK)/Ras/phosphoinositide 3-kinase signaling, which endow GBM with unlimited proliferative capacity [24, 25]. The gene discussed is RB1; the disease is glioblastoma.