RBL1 and neoplasm: In a GFAP-CreER; PtenloxP/loxP; Trp53loxP/loxP; Rb1loxP/loxP; Rbl1−/− Genetically Modified Murine Model (GEMM) of glioblastoma where tumor can spontaneously arise in different regions of the cerebrum [16], glioblastoma that arose near the SVZ were more likely to be of proneural subtype.