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PAX8 and PAX5 are differentially expressed in B‐cell and T‐cell lymphomas
Author(s) -
Morgan Elizabeth A,
Pozdnyakova Olga,
Nascimento Alessandra F,
Hirsch Michelle S
Publication year - 2013
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/his.12020
Subject(s) - pax5 , b cell , antibody , lymphoma , biology , immunohistochemistry , lymph node , pax8 , pathology , microbiology and biotechnology , immunology , medicine , gene , transcription factor , biochemistry
Aims: The purpose of this study was to evaluate the expression patterns of B‐cell specific activator protein (BSAP)/PAX5 and PAX8 in a wide variety of B‐cell and T‐cell neoplasms. Methods and results: A wide range of B‐cell and T‐cell neoplasms were subjected to immunohistochemical staining with antibodies against BSAP/PAX5 and PAX8 (polyclonal, pPAX8; monoclonal, mPAX8). Ten non‐neoplastic lymph node specimens were examined with the same panel. All of the tested neoplastic and non‐neoplastic B‐cells reacted with the BSAP/PAX5 and pPAX8 antibodies, but did not show reactivity with the mPAX8 antibody. All tested T‐cell neoplasms were negative using the BSAP/PAX5, pPAX8 and mPAX8 antibodies. Conclusions: This is the first study to show the absence of reactivity to an mPAX8 antibody in an expanded panel of B‐cell lymphomas as well as in a variety of T‐cell neoplasms. In contrast to the mPAX8 antibody, the pPAX8 antibody shows nuclear positivity in non‐neoplastic B cells and mature B‐cell neoplasms; however, this expression is probably a result of cross‐reactivity with PAX5. Given that many laboratories use the pPAX8 antibody, a clear understanding of the differential staining patterns is necessary. The differential diagnosis of a B‐cell lymphoma should be entertained when a pPAX8‐positive, epithelial marker‐negative neoplasm of uncertain primary origin is encountered.