DLL4 and neoplasm: To study the effects of endothelial Dll4 overexpression on tumor growth, LLC cells were injected subcutaneously in D4BE (non-induced Tie2-rtTA TetO7-Dll4), in D4BE + Doxy (doxycycline-induced TetO7-Dll4, which served as induction controls) and D4OE (doxycycline-induced Tie2-rtTA TetO7-Dll4) mice (n = 6).