KDR and neoplasm: To overcome this hurdle, self-assembled siRNA layered nanoparticles (nanoplexes) comprising PEI and PEGylated Ar3-Gly-Asp (RGD) peptide ligand were synthesized to target the tumor neovasculature expressing integrin to attenuate the VEGFR2 expression and tumor angiogenesis [131,132,133,134,135,136,137,138,139].