While RGD's tumor-targeting efficiency is constrained by passive diffusion and heterogeneous integrin expression, internalizing RGD peptide (iRGD), a cyclic peptide, exhibits an enhanced tumor-selective accumulation and tumor cell-specific affinity by protease-cleavable design and dual-receptor engagement involving integrin and Neuropilin-1 (NRP-1) [[19], [20], [21]]. This evidence concerns the gene NRP1 and neoplasm.