DLL4 and neoplasm: We generated RT2 Tie2-rtTA-M2 TetO7-Dll4 mice and simulated a therapeutic intervention by inducing endothelial Dll4 overexpression in a mouse group (RT2 D4OE) vs. non-induced control group (RT2 D4BE) (n = 10) during the developing RT2 tumor stage (10 – 13.5 weeks old animals).