Apoptosis is induced by certain cytokines including TNF and Fas ligand in the TNF family through their death domain containing receptors. TRAIL/Apo2L is a new member of the TNF family and induces apoptosis of a variety of tumor cell lines. DR4 and DR5 are the recently identified functional receptors for TRAIL, and DcR1/TRID is a decoy receptor. Another member of the TRAIL receptor family was more recently identified and designated DcR2, TRAIL-R4, or TRUNDD. DcR2 has an extracellular TRAIL-binding domain but lacks intracellular death domain and does not induce apoptosis. Like DR4 and DR5, DcR2 transcript is widely expressed in normal human tissues. Overexpression of DcR2 attenuated TRAIL-induced apoptosis.