Tumor necrosis factor (TNF , TNF -a , cachectin ) is a pleiotropic pro-inflammatory cytokine produced mainly by activated macrophages and monocytes. In addition to functioning immonomodulacyjnego TNF also has antitumor effect by inhibiting the growth of certain tumors , and even causing regression . TNF Therefore , in spite of its toxicity , is used in cancer therapy , mainly non-operative limb sarcomas and melanomas .