Objectives: The diagnosis of T-lymphoblastic leukemia/lymphoma (T-ALL) involving the thymus can be difficult to establish since neoplastic T lymphoblasts show significant phenotypic overlap with both normal thymocytes and thymocytes from epithelial thymic neoplasms (thymomas). LIM Domain Only 2 (LMO2) gene translocations have been implicated in the pathogenesis of a small subset of T-ALLs, and LMO2 protein has recently been reported to be expressed in a large proportion of T-ALLs.
Methods: In this study, we tested specificity of LMO2 for distinction between neoplastic and nonneoplastic T-precursor cells in thymus and bone marrow.
Results: Our findings show that LMO2 is expressed in neoplastic lymphoblasts of T-ALL and is absent in thymocytes of normal thymuses or thymomas.
Conclusions: LMO2 is therefore a useful marker for immunophenotypic assessment of thymic neoplasms.
Keywords: Immunohistochemistry; LMO2; T-ALL.
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