CCND1 and mantle cell lymphoma: SOX11 is a good diagnostic marker for MCL, particularly in the diagnosis of cyclin D1-negative MCL and to distinguish between aggressive MCL and CD5-positive DLBCL.[7] However, because a small subset of MCL is SOX11-negative, the diagnostic applications of SOX11 should be incorporated in an immunohistochemistry panel approach rather than used alone.