[1194] Nuclear Staining of SOX11 Is a Reliable Immunohistochemical Marker for Mantle Cell Lymphoma

J Gao, L Peterson, Y Chen. Northwestern University Feinberg School of Medicine, Chicago, IL

Background: SOX genes encode a family of transcriptional factors involved in regulating neural crest development. Overexpression of SOX11 has been reported in malignant glioma. SOX11 shares sequence homology with SOX4, a transcription factor crucial for B cell development. A recent study reported specific nuclear expression of SOX11 in mantle cell lymphoma (MCL). The findings indicate that SOX11 may serve as a marker for diagnosis of MCL. So far, the data reported is very limited.
Design: In the current study, we evaluated 43 cases with a confirmed diagnosis of MCL and compared SOX11 expression in these cases with cyclin D1 expression and FISH analysis for t(11;14). We also tested SOX11 expression in non-MCL lymphomas including 50 cases of CLL/SLL, 22 follicular lymphomas (FL) and 20 diffuse large B cell lymphomas (DLBCL). Expression of SOX11 was examined by immunohistochemical stain on formalin fixed, paraffin embedded whole tissue sections.
Results: The diagnosis of MCL was confirmed either by flow cytometric immunophenotyping and positive cyclin D1 staining, and/or FISH for t(11;14). Of the 43 cases, 39 (90.7%) showed positive nuclear staining of SOX11 in a diffuse homogeneous pattern, including 5 cases of CD5-negative MCL and 2 cases of blastoid variant. The positive nuclear staining was seen in >50% cells in 34 cases (87.1%), 20-30% cells in 4 cases, and 10% in 1 case. Of the four SOX11 negative MCL cases, two were also negative for cyclin D1; but FISH showed positive t(11;14). The SOX11 staining was in agreement with cyclin D1 staining in 95% of the cases. We also tested SOX11 expression in non-MCL lymphomas. None of the CLL/SLL (50 cases) or FL (22 cases) showed positive homogeneous nuclear stainging, but demonstrated perinuclear granular staining most prominent in prolymphocytes and centroblasts. The staining pattern was different from that in MCL. Of the 20 DLBCL, 19 were negative for nuclear staining but showed perinuclear granular staining. One DLBCL demonstrated both cytoplasmic and nuclear staining.
Conclusions: Our study demonstrated that positive nuclear staining of SOX11 is an immunohistochemical marker for MCL. It may be useful as a complement to cyclin D1 for the diagnosis of MCL.
Category: Hematopathology

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 117, Tuesday Morning