IRF4 and plasma cell myeloma: However, divergent experimental evidence has demonstrated the tumor-suppressive function of miR-125b in the U266 MM cell line, since its transduction was able to induce a significant increase in death rate compared to control cells by the downregulation of BLIMP-1, IRF4, and SYNDECAN-1 (CD138), a cell surface molecule expressed by myeloma and primary plasma cells.23