BIRC5 and hepatocellular carcinoma: In the present study, an RGD-modified MRI-visible non-viral vector, polyethylene glycol-grafted polyethylenimine functionalized with superparamagnetic iron oxide nanoparticles (RGD-PEG-g-PEI-SPION), was synthesized to specifically deliver Survivin siRNA to HCC cells and sensitively detecting the tumor cells by MRI in vitro and in vivo.