NRP1 and glioblastoma: In comparison to control cells (n = 10 NCR-nu/nu mice), LN229 cells expressing Nrp1 shRNAs (n = 10 NCR-nu/nu mice) generated significantly larger intracranial tumors (Fig 2C–2F and S4 Fig), suggesting a critical role for Nrp1-dependent signaling mechanisms in GBM growth and progression.