Consistent with these findings, CD31+ vascular structures with normal morphology were visualized even within cleaved caspase 3+ tumor areas of drug‐treated mice, and NVP‐Iso did not reduce the proliferation of primary endothelial cells in culture (Fig. S4B), suggesting that tumor tissue degeneration is not attributable to a primarily vascular effect of the drug. Here, PECAM1 is linked to neoplasm.