PECAM1 and prostate cancer: Immuno-histochemical staining for the endothelial cell markers human CD31 (huCD31) (Fig. 3), CD34 and vWF (not shown) in primary xenografts of human benign prostate tissue and prostate cancer tissue demonstrated a dramatic increase in microvessel density (MVD) during the 14 days after transplantation (Fig. 3b–g) as compared to the MVD in the corresponding initial tissue specimen harvested before transplantation (Fig. 3a).