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Identifies the MUM1 gene product, a protein overexpressed in the late plasma-cell–directed stages of B-cell differentiation. It is positive in multiple myeloma, lymphoplasmacytic lymphoma, Reed-Sternberg cells of Hodgkin lymphoma, and about 50% of diffuse large B-cell lymphomas. It shows low expression in marginal zone, follicular, and CLL/SLL lymphomas, and is negative in Burkitt lymphoma. MUM1 expression is associated with poorer prognosis in diffuse large B-cell lymphoma.
Tissue Block: Formalin-fixed, paraffin-embedded (FFPE) tumor block preferred.
Unstained Slides: Recommended 2 charged slides per stain requested (minimum of 1 slide per stain), baked or unbaked.
Fixation: Tissue must be fixed in 10% neutral buffered formalin for 6–72 hours.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.