DLL4 and hemangioma: Previous work in our laboratory has shown that members of the Notch signaling pathway, namely receptors and ligands, are expressed in hemangiomas.[19] In particular, we have demonstrated that the endothelial-associated NOTCH1, NOTCH4, and JAGGED-1 genes are highly expressed in involuting hemangiomas and HemECs, while DELTA-LIKE LIGAND-4 (Dll4) showed an intermediate level of expression in HemECs.