Antitumor effects of Ad-Endo combined with dl 1520 on GC SGC-7901 xenografts in nude mice. A) The plasma concentration of endostatin in mice treated with a single intratumoral injection of Ad-Endo (5×108 pfu) alone or in combination with dl 1520 (5×108 pfu). Blood plasma was sampled at the indicated time points, and the endostatin concentration was detected by ELISA (n=3) (two-way ANOVA, **p<0.01 compared to Ad-Endo alone). B, C) The growth inhibition of SGC-7901 xenografts by Ad-Endo or/and dl 1520. B) The growth curves of SGC-7901 xenografts (two-way ANOVA, *p<0.01 compared to the control group; **p<0.01 compared to other three groups). C) Tumor weights (one-way ANOVA, *p< 0.01 compared with control group; **p<0.01 compared with the Ad-Endo+dl 1520 group). D) Immunohistochemical assays of SGC-7901 xenografts to detect the expression of endostatin (upper), CD34 (middle) and the Ad hexon protein (lower) (×200). Brown staining indicates gene expression, and blue staining represents the cell nuclei. CD34, a marker of vascular endothelial cells, is used to assess the microvessel density in the tumor. Hexon staining indicates Ad replication.