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PAX‐5 is invariably expressed in B‐cell lymphomas without plasma cell differentiation
Author(s) -
Dong H Y,
Browne P,
Liu Z,
Gangi M
Publication year - 2008
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2008.03091.x
Subject(s) - cd20 , lymphoma , b cell , immunohistochemistry , pathology , plasma cell , cell , biology , b cell lymphoma , cellular differentiation , rituximab , cancer research , medicine , immunology , antibody , gene , genetics , biochemistry
Aims: The B‐cell‐specific transcription factor PAX‐5 is physiologically expressed in normal B cells and silenced in plasma cells. The aim of this study was to determine whether PAX‐5 expression is universal among B‐cell malignancies. Methods and results: A wide spectrum of B‐cell malignancies were subjected to immunohistochemical analysis for PAX‐5 expression. The study was especially focused on cases lacking CD20, such as precursor B‐cell acute lymphoblastic leukaemia (preB‐ALL), CD20− B‐cell lymphomas, classical Hodgkin’s lymphoma (CHL) and B‐cell lymphomas with significant plasmacytic differentiation. Strong PAX‐5 expression was identified, without exception, in all cases of CD20+ B‐lymphoproliferative disorders. It was also invariably detected in 31/31 cases of preB‐ALL, 14/14 cases of CD20− diffuse large B‐cell lymphoma without plasmacytic differentiation and 26/26 CD20− B‐cell lymphoma status post rituximab treatment. The vast majority of CHLs had unequivocal PAX‐5 expression of varying intensity (80/86). However, variants of B‐cell malignancies with characteristic plasmacytic differentiation exhibited no detectable PAX‐5 expression (0/17). Conclusions: PAX‐5 is the most sensitive and reliable immunohistochemical marker for B‐cell malignancies. Lack of PAX‐5 expression correlates with the presence of marked plasma cell differentiation.