Mapatumumab, a recombinant, fully human agonist IgG1 monoclonal antibody that binds with high affinity to TRAIL-R1, shows cytotoxic activity in vitro, and inhibits the growth of human tumour cell lines, including colorectal cancer cell lines, in xenograft models in vivo. The gene discussed is TNFRSF10A; the disease is neoplasm.