As shown in Fig. 6a, tumor growth was reduced by both endothelial Dll4 overexpression and doxorubicin administration to Dll4BE mice, while the concomitant administration of doxorubicin to Dll4OE mice further reduced the tumor growth by 15% at endpoint (p < 0.05; Fig. 6b). The gene discussed is DLL4; the disease is neoplasm.