Tumor necrosis factor alpha (TNF-α), also known as cachectin and TNFSF1A, is the prototypic cytokine of the the TNF superfamily. It is a multifunctional molecule involved in the regulation of a wide spectrum of biological processes including cell proliferation, differentiation, apoptosis, lipid metabolism, and coagulation. TNF-α is produced mainly by macrophages, and large amounts of this cytokine are released in response to lipopolysaccharide, other bacterial products, and Interleukin-1 (IL-1). Two receptors mediating the TNF-α function have been identified, the ubiquitous TNF RI from which most signaling are derived, and the hematopoietic cell-restricted TNF RII. TNF-α has been implicated in the pathogenesis of a variety of human diseases including autoimmune diseases, insulin resistance, and cancer.