TNFSF10, also known as TRAIL or Apo-2 ligand (Pitti et al, 1996), is a member of the TNF superfamily, and since its discovery it has been used as an antitumour protein because of its ability to induce apoptosis in a variety of human cancer cell lines while leaving normal cells unaffected (Walczak et al, 1999). The gene discussed is TNF; the disease is cancer.