RB1 and glioblastoma: To investigate mechanisms of GSC/vascular interactions in the context of syngeneic, immuno-competent brains, we sequentially introduced mutations commonly found in human GBM (RTK activation,p53 and RB inactivation) in primary murine SVZ NSC to generate fully transformed, GSC-like cells and genetically-matched immortalised NSC (Network, 2008).