tumor necrosis factor, TNF-like tumor necrosis factor PIRSF:PIRSF500467 Category=gene. tumor necrosis factor ligand superfamily member 2 TNF-alpha protein cachectin PR:000000134 TNFa tumor necrosis factor alpha TNF-a A tumor necrosis factor, TNF-like that is a translation product of the human TNF gene or a 1:1 ortholog thereof. Tumour necrosis factor alpha (TNF) is a pleiotropic cytokine that mediates apoptosis, cell proliferation, immunomodulation, inflammation, viral replication, allergy, arthritis, septic shock, insulin resistance, autoimmune diseases, and other pathological conditions. TNF transduces these cellular responses through two distinct receptors: type I, which are expressed on all cell types, and type II, which are expressed only on cells of the immune system and endothelial cells.