NRP1 and glioblastoma: Given that Nrp1 can modulate VEGF-A and TGFβ signaling in GBM cells (Fig 4) and that Nrp1 suppresses GBM growth within the context of the brain microenvironment (Fig 2), we next analyzed links between Nrp1 expression and GBM recurrence following neutralization of VEGF-A with bevacizumab.