NRP1 and neoplasm: Following proteolytic cleavage of the iRGD peptide after binding to integrins, a CendR motif (C‐terminal arginine or lysine residue) is exposed which interacts with neuropilin‐1 (NRP‐1) receptors present on tumor cells and vasculature, leading to enhanced tissue penetration and cellular uptake via receptor‐mediated endocytosis.174, 175, 176, 177