On the other hand, MUM1/IRF4 functions as a tumor suppressor in c-MYC-induced B-cell leukemia.     ///    "MUM1/IRF4 has been found to induce c-MYC expression, and in turn, MYC transactivates MUM1/IRF4, creating a positive autoregulatory feedback loop. "    ///    "The present rare case arouses interest in view of the possible ""dual"" activation of both c-MYC and MUM1/IRF4 through two independent dual-translocations, c-MYC/BCL-2 and IRF4/BCL-2.. "    ///    "However, the interfollicular larger cells showed plasmacytic differentiation with diminished CD20, Bcl-2, Bcl-6, and positive intracytoplasmic IgM, and co-expression of MUM1/IRF4 and CD138 with increased Ki-67-positive cells (> 90%). "    ///    "The intrafollicular tumor cells had a germinal center phenotype with the expression of surface IgM, CD10, Bcl-2, Bcl-6, and MUM1/IRF4. "