HRAS and neoplasm: In this study, to improve the penetration of the anti-p21Ras scFv into tumor tissues via endocytosis, we connected the RGD4C sequence to the N terminus of the anti-p21Ras scFv to construct RGD4C-p21Ras-scFv prokaryotic expression vectors, then the fusion protein RGD4C-p21Ras-scFv (RGD4C-scFv and RGD4C-linker-scFv) was expressed and purified and subsequently investigated the effects of targeting and penetrating the human colorectal cancer cell line SW480 as well as the antitumor effect in vitro.