As described above, Jagged1 antagonizes Dll4 during sprouting angiogenesis [52], and overexpression of Jagged1 in tumor cells has been shown to enhance neovascularization and tumor growth [58]; however, the role of Jagged1 in pathological angiogenesis (including tumor angiogenesis) is not yet fully understood. This evidence concerns the gene DLL4 and neoplasm.