APLN and neoplasm: To date, a large number of promoters of tumor angiogenesis have been discovered (Figure 1), such as the vascular endothelial growth factor (VEGF) family, angiopoietins (ANGPTs), fibroblast growth factors (FGFs), platelet-derived growth factor (PDGF), APLN (Apelin)/APLNR (G protein-coupled receptor APJ) pathway, hepatocyte growth factor (HGF)/hepatocyte growth factor receptor (c-MET), chemokines, Eph/Ephrin signaling, etc. Their targets, mechanisms, downstream signals and research status in OC are discussed below in detail.