PECAM1 and neoplasm: Conversely, there was an increase in the number of functional (DiOC7+) blood vessels and the percentage of functional vasculature in orthotopic MCF-7 tumors on day 4 compared to control (Figure 3B, P < 0.05); however, there was no significant change in the total (CD31+) tumor vasculature with paclitaxel treatment in orthotopic tumors.