Using xenografted osteosarcoma as the model, we found that Ad5-Eag1-shRNA reduced intratumoral MVD counts based on CD31 immunohistochemistry (5.0 ± 2.7 tumor vessels per high power field, n = 10) compared to Ad5-Control-shRNA or saline (17.8 ± 1.9 and 19.5 ± 3.1 tumor vessels per high power field, respectively, n = 10, p < 0.001, Figure 3A). This evidence concerns the gene PECAM1 and osteosarcoma.