When tumor sections were immunohistochemically stained with an anti-CD31 antibody, the expression of CD31 in the tumor was reduced in mice injected with high-dose pardaxin (25 mg/kg; 0.5 mg/day) for 14 days (Figure 4d), whereas the expression of CD31 of the control (untreated) group remained at a relatively high level (Figure 4a). This evidence concerns the gene PECAM1 and neoplasm.