PGF and cancer: In a growing cancer there is a constant production of angiogenesis inducers, including vascular endothelial growth factor (VEGF)-A, basic fibroblast growth factor (bFGF, also known as FGF), angiogenin, tumor necrosis factor (TNF)-α, granulocyte colony-stimulating factor (G-CSF), platelet-derived endothelial growth factor (PDGF), placental growth factor (PGF), transforming growth factor (TGF)-α, TGF-β, interleukin-8 (IL-8), hepatocyte growth factor (HGF), and epidermal growth factor (EGF) [22].