A cell protein that can attach to certain molecules in some cancer cells and may kill the cells. Apo-2L is being studied in the treatment of cancer. Also called TNF-related apoptosis-inducing ligand, TRAIL, and tumor necrosis factor-related apoptosis-inducing ligand. OR A humanized monoclonal antibody directed against 1D10, a polymorphic determinant on the HLA-DR beta chain that is expressed on normal and neoplastic B cells. Apolizumab induces complement-mediated cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and apoptosis of 1D10 antigen-positive B cells in vitro.