They contribute to the tumor microenvironment by releasing pro-inflammatory cytokines; growth factors, such as the platelet-derived growth factor (PDGF), platelet factor 4, transforming growth factor beta (TGFb), and vascular endothelial growth factor (VEGF); thrombospondin; and other mediators which serve as potent mitogens or adhesive glycoproteins for diverse cell types, including ovarian surface epithelium. This evidence concerns the gene PF4 and neoplasm.