IMMUNOHISTOCHEMISTRY: LMO2

LMO2 IS A TRANSCRIPTION FACTOR THAT REGULATES VASCULAR AND HEMATOPOIETIC SYSTEMS AND IS INVOLVED IN HEMATOLYMPHOID NEOPLASIA. LMO2 IS PREFERENTIALLY EXPRESSED BY GERMINAL CENTER B CELLS AND MAY ALSO BE EXPRESSED IN ERYTHROID AND MYELOID PRECURSORS AND IN MEGAKARYOCYTES. EXPRESSION HAS BEEN OBSERVED IN CASES OF LYMPHOBLASTIC LEUKEMIA AND ACUTE MYELOID LEUKEMIA. IT IS RARELY EXPRESSED IN MATURE T, NATURAL KILLER, AND PLASMA CELL NEOPLASMS AND IS ABSENT FROM NON-HEMATOLYMPHOID TISSUES EXCEPT FOR ENDOTHELIAL CELLS. IN THE DIAGNOSIS OF B-CELL LYMPHOMAS, LMO2 CAN BE USEFUL IN AN IMMUNOHISTOCHEMICAL PANEL TO ASSIGN A GERMINAL CENTER PHENOTYPE THEREBY HELPING IN THE CLASSIFICATION OF LYMPHOMAS. LMO2 IS USED TO DIFFERENTIATE FOLLICULAR LYMPHOMA (LMO2 POSITIVE) FROM NODAL MARGINAL ZONE LYMPHOMA (LMO2 NEGATIVE).