DLL4 and neoplasm: The formation of vascular networks in the tumor microenvironment (TME) involves various factors, including but not limited to Vascular Endothelial Growth Factor (VEGF), Platelet-Derived Growth Factor (PDGF-B), Interleukin-8 (IL-8), Delta-like Ligand 4 (Dll4), and the Transforming Growth Factor (TGF-β) families (50, 51).