TNF and cancer: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising agent for cancer therapy, as TRAIL-based therapeutics have been shown to be more effective inducers of apoptosis in cancer cells than in normal cells.1, 2, 3 Natural TRAIL is a type II membrane protein, and its membrane form is cleaved to produce a soluble, biologically active cytokine.4 The soluble TRAIL (sTR) protein exists as a homotrimer, and a single zinc atom is chelated by the Cys230 of each monomer.