RB1 and central nervous system cancer: Type III cases are characterized by their IDH wild-type status and represent about 20% of grade II–III gliomas; these tumors are characterized by molecular abnormalities typically observed in glioblastomas, such as amplification of EGFR, PDGFRA, CDK4, MDM2, and MDM4, deletion or mutation of PTEN, NF1, RB1, CDKN2A, and CDKN2B and amplification of class II PI3K genes; type III gliomas were associated with a negative outcome [99].