TNFRSF1B and plasma cell myeloma: We found accordingly that only the TNFR1-specific TNF mutant Fc-TNF(32W/86T) but not TNC-scTNF(143N/145R), a highly active TNFR2-specific TNF mutant-based fusion protein8, was able to induce cell death in myeloma cells in the presence of MLN4924 (Fig. 4a).