Tumor necrosis factor is a cytokine and member of the TNF superfamily, which consists of various transmembrane proteins with a homologous TNF domain. It is the first cytokine to be described as an adipokine as secreted by adipose tissue. TNF signaling occurs through two receptors: TNFR1 and TNFR2. TNFR1 signaling tends to be pro-inflammatory and apoptotic, whereas TNFR2 signaling is anti-inflammatory and promotes cell proliferation. Suppression of TNFR1 signaling has been important for treatment of autoimmune diseases, whereas TNFR2 signaling promotes wound healing. The primary role of TNF is in the regulation of immune cells. TNF, as an endogenous pyrogen, is able to induce fever, apoptotic cell death, cachexia, and inflammation, inhibit tumorigenesis and viral replication, and respond to sepsis via IL-1 and IL-6-producing cells. Dysregulation of TNF production has been implicated in a variety of human diseases including Alzheimer's disease, cancer, major depression, psoriasis and inflammatory bowel disease (IBD).