Growth factors are expressed in in every system of the body, including that of the lymphoid/lymphocyte immune system. A key cytokine involved in that process is the tumor necrosis factor (TNF-alpha) protein. TNF-α is an adipokine that is involved in systemic inflammation and regulates immune cells in response to disease. Recombinant TNF-α is also called tasonermin , it is used as an immunostimulant and is the primary active ingredient in the European drug Beromun. Gold Biotechnology additionally has a His-tagged TNF-α, convenient for protein isolation experiments as well as a TNF-α variant which has been shown to express anti-tumor activity in mice as compared to normal murine TNF-α.