NRP1 and neoplasm: The effectiveness of APPA self-assembled peptosomes as nanoparticle adjuvant may be due to several of their characteristics: (1) the plasma half-life of the peptosome is much longer than that of NRP1-binding peptides, such as iRGD; (2) the EPR effect of peptosome promoted the enrichment in tumor vessels; (3) each peptosome consists of multiple ligands for binding with NRP1 and integrin αvβ3 receptors to ensure the activation of NRP1-mediated endocytosis pathway.