RB1 and glioblastoma: Major patterns in these tumors include components of the Ras-MAPK and PI3K-AKT-mTOR signaling pathways being affected in the plurality (88%; 80 of 91) of malignant gliomas and disruption of the p53 and RB tumor suppressor networks also occurring in a high proportion of glioblastomas: 87% (79 of 91) and 78% (71 of 91), respectively [25].