– Tumor necrosis factor alpha (TNFα) is the prototypic ligand of the TNF superfamily. TNFα forms a homotrimer and functions by activating two types of receptors TNF-R1 (TNF receptor type 1,p55R) and TNF-R2 (TNF receptor type 2,p75R). TNFα is a pleiotropic cytokine that is capable to promote inflammation, to induce apoptotic cell death, and to inhibit tumorigenesis and viral replication. TNFα is a potent lymphoid factor that exerts cytotoxic effects on a wide range of tumor cells and certain other target cells.