These contents exert different functions during cancer; some inhibit cancer progression, including miR-503 [46] and miR-126 [47], while others promote cancer progression, including MALAT1[48], S100A16 [49], delta-like protein 4 [50], angiopoietin-2 (Ang2) [51], and carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) [52]. Here, DLL4 is linked to cancer.