[1382] Characterization of α-Synuclein Expression in Paraffin-Embedded Bone Marrow Biopsy Tissue Sections: A New Diagnostic Tool for Acute Erythroid Leukemia and Acute Megakaryoblastic Leukemia

RW Maitta, P Bhattacharyya, JZ Gong, JM Albanese, J Sunkara, JG Pizzolo, H Ratech. Montefiore Med Ctr / Albert Einstein Coll Med, Bronx, NY; Hackensack Univ Med Ctr, Hackensack, NJ; Labcorp, Research Triangle Park, NC

Background: Alpha-synuclein is a component of the Lewy body, which is found in Parkinson's disease and other dementias. Although α-synuclein is expressed in normal platelets, megakaryocytes and red blood cells, its role in both normal hematopoiesis and leukemogenesis is unknown. Of interest, closely related γ-synuclein is elevated in some cancers. Therefore, we studied the expression of α-synuclein in a comprehensive panel of bone marrow diseases.
Design: Using a mouse monoclonal antibody to human α-synuclein (Novocastra Newcastle, UK), we immunohistochemically stained formalin-fixed, paraffin-embedded bone marrow biopsy tissue sections, which included reactive marrow (N= 7), myeloproliferative neoplasm (MPN; N= 6), myelodysplastic syndrome (MDS; N=4), acute myeloid leukemia (AML; N=26), acute erythroid leukemia (EryL; N=5) and acute megakaryoblastic leukemia (MegL; N=5).
Results: We confirmed that in reactive bone marrows the platelets, megakaryocytes and erythroid precursors stained positively for α-synuclein. In contrast, there was no expression of α-synuclein in the granulocytic cell lineage at all stages of maturation. Alpha-synuclein was easily identified in erythroid precursors, and in both hypo- and polylobated megakaryocytes, in all cases of MPN, MDS, as well as in residual non-neoplastic erythroid precursors and megakaryocytes in AML. The blasts in all cases of AML were negative for α-synuclein. Among cases of EryL, we observed positive staining for α-synuclein in the erythroid precursors but not in the blasts. Among cases of MegL, in addition to the megakaryocytes, a minority of the blasts (∼20%) stained positively for α-synuclein in a coarsely granular, cytoplasmic pattern.
Conclusions: We report that α-synuclein is expressed in megakaryocytes and erythroid precursors in a broad spectrum of bone marrow diseases. In particular, α-synuclein may be a useful marker for confirming the diagnosis of EryL and MegL.
Category: Hematopathology

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 168, Tuesday Afternoon


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