title: Expression of LEF1 in mantle cell lymphoma.
abstract: Small lymphocytic lymphoma/chronic lymphocytic leukemia (CLL/SLL) and mantle cell lymphoma (MCL) usually are distinctly different in regard to clinical presentation, morphology, immunophenotype and molecular/genetic findings. In spite of this, select cases may show overlapping characteristics and represent a diagnostic challenge. Recently LEF1 staining was identified as a fairly characteristic finding in CLL/SLL, with positivity identified in up to 95% of cases. LEF1 staining has not been reported as being present in cases of MCL, making this stain a useful tool in distinguishing these diagnoses. We identified an index case of MCL with cyclin D1 expression and the presence of the typical t(11;14) IGH-CCND1, which expressed LEF1. Subsequently, we assessed LEF1 immunohistochemical staining in a series of 23 cases of MCL, as confirmed by staining for cyclin D1 and/or SOX11. We found expression present in one additional case, and evaluated some published literature suggesting a frequency of 4-9% expression of LEF1 by MCL. LEF1 expression by immunohistochemistry in MCL is unusual but can be seen rarely, and could represent a potential diagnostic pitfall.
authors.affiliation: Neogenomics, Aliso Viejo, CA, United States; Department of Hematopathology, M.D. Anderson Cancer Center/University of Texas, Houston, TX, United States. Electronic address: dennis.omalley@neogenomics.com.
authors.forename: Dennis P
authors.initials: DP
authors.lastname: O'Malley
authors.affiliation: University of Iowa Hospitals and Clinics, United States.
authors.forename: John P
authors.initials: JP
authors.lastname: Lee
authors.affiliation: University of Iowa Hospitals and Clinics, United States. Electronic address: abellizzi@helathcare.uiowa.edu.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Bellizzi
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D016130:Immunophenotyping / Q000379:methods; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000378:metabolism*; D020522:Lymphoma, Mantle-Cell / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged
chemical_list: D014408:Biomarkers, Tumor; C497573:LEF1 protein, human; D051821:Lymphoid Enhancer-Binding Factor 1
keywords: Chronic lymphocytic leukemia; Diagnosis; Immunohistochemistry; LEF1; Mantle cell lymphoma