SFNs not only overcame their inherent instability but also facilitated dramatic tumor accumulation and penetration in an orthotopic breast cancer mouse model in vivo, resulting in a synergistic effect between iRGD and SFNs and a consequent increase in tumor necrosis or apoptosis, reduction in tumor angiogenesis, and suppression of Ki-67-positive tumor cell proliferation. This evidence concerns the gene MKI67 and neoplasm.