RBL1 and glioblastoma: To confirm our clinical finding, we tested the distribution of glioblastoma subtypes in a GFAP-CreER; PtenloxP/loxP; Trp53loxP/loxP; Rb1loxP/loxP; Rbl1−/− GEMM model where glioblastoma can arise anywhere in the cerebrum [16].