NRP1 and cancer: Whereas the ATW-NRP1 peptide binds to the ectodomain of NRP1 and has been previously used as a cancer-targeting tool to enhance the photodynamic destruction of brain tumors [52,53,58], the hydrophobic MTP-NRP1 targets the transmembrane domain of the receptor [45] and was shown to efficiently reduce tumor growth in breast- or brain-tumor models [47,48].