PECAM1 and neoplasm: To determine the in vivo effect of FOXQ1 on tumor angiogenesis, MVD was evaluated by immunohistochemical staining of tumor specimens for the blood vessel markers CD31 and CD34, and the number of CD31+(left panel of Figure 4E; P<0.05) and CD34+(right panel of Figure 4E; P<0.05) blood vessels was significantly decreased in DLD1-shFOXQ1 compared with DLD1-shControl tumors.