PLXNA1 and glioblastoma: 1D). Downregulating Nrp1 expression by lentiviral mediated shRNA knockdown (Nrp1-KD) also caused loss of Nrp1 immunostaining, indicating specificity of the antibody (Supp. Figure 4). TCGA data correlating expression of these three transcripts (Nrp1, PlxnA1, Sema3A) with survival show that patients in the lower quartile of expression for all three markers live significantly longer than patients in the higher quartile of expression for both GBM and low-grade gliomas (Supp. Figure 5).