In a retrospective biospecimen genetic study performed by McLendon et al., the three pathways RTK-RAS-PI3K, p53, and RB were observed to be altered in 88%, 87%, and 78% of glioblastoma cases, respectively, with nearly 75% of the samples harboring alterations in all three cascades [100]. The gene discussed is RB1; the disease is glioblastoma.