PECAM1 and malignant colon neoplasm: The antitumor effect of heparin–polyethyleneimine NPs delivering plasmids that express mouse survivin T34A was evaluated in colon cancer cells both in vitro and in vivo: immunostaining of CD31 with tetramethylrhodamine-conjugated antibodies allowed the visualization of blood vessels; TUNEL assay and propidium iodine were used to detect apoptosis, and β-galactosidase staining allowed the verifying of the transfection ability of these NPs.