Comparable to morphological changes observed in subcutaneous xenografts, Dll4 overexpression was shown to restrict PECAM-network branching but increase papilloma vessel lumen calibers (p < 0.05, Fig. 3c), α-SMA-positive mural cell recruitment (p < 0.01, Fig. 3d,e) and promote vessel competence as indicated by significantly increased lectin perfusion in papillomas developed by D4OE vs. D4BE (p < 0.05, Fig. 3f,g). Here, ACTA1 is linked to papilloma.