APLN and neoplasm: With the advances in cellular and molecular biology, various biomolecules involved in tumor angiogenesis have been identified, such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), fibroblast growth factor 2 (FGF-2), chemokines, ephkrine, apelin (APLN) [89,90,91,92].