On the one hand, RGD (arginine-glycine-aspartic acid) may interact with the overexpressed v3 integrin in tumor vasculature to target tumor endothelium; on the other, RGDK can bind to the neuropilin-1 (Nrp-1) receptor on tumor cells, facilitating cancer cell penetration and uptake (Teesalu et al., 2009; Desgrosellier and Cheresh, 2010; Marelli et al., 2013). This evidence concerns the gene NRP1 and neoplasm.