CXCL8 and neoplasm: Furthermore, soluble factors such as IL-10 and TGF-β, as well as pro-angiogenic factors (vascular endothelial growth factor -VEGF, platelet-derived growth factor - PDGF, fibroblast growth factor -FGF, IL-8), play a role in turning off the effector cells present in the tumor and promoting tumor angiogenesis [16,17].