Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL/Apo2 L), known as a cytokine of the TNF superfamily, is a type II transmembrane protein ligand that induces caspase-dependent apoptosis via the extrinsic pathway in a wide variety of human cancer cells while having negligible cytotoxicity toward normal cells4–6. This evidence concerns the gene TNF and cancer.