PAX5 expression in nonhematopoietic tissues. Reappraisal of previous studies.
The Pax gene family encodes transcription factors with similar structures but distinctive roles in development and with limited expression in adult tissues. Reexpression of PAX proteins is frequently observed in human cancers, reflecting recapitulation of embryologic or developmental function. Defining expression of PAX family members is important in the immunohistochemical differential diagnosis of cancer, understanding oncogenesis, and defining targets for therapy. Immunostaining for PAX5 has become a commonly used technique in differential diagnosis of B-lineage hematologic malignancies. In seeking to define the range and degree of expression of PAX5 in nonhematologic pediatric cancers by immunohistochemical analysis with the anti-PAX5 monoclonal antibody routinely used in research and diagnosis, we observed strong immunostaining in a number of malignant tissues, including Wilms tumor. The pattern of expression of PAX5 in Wilms tumor was found to be identical to that of PAX2, raising the possibility of antibody cross-reactivity. This was subsequently confirmed by Western blotting and immunostaining of transfected cells and quantitative reverse transcriptase-polymerase chain reaction. Since the same PAX5 monoclonal antibody has been used consistently in the literature, these findings indicate a need for reappraisal of published PAX5 immunostaining results.
Unit of Molecular Haematology and Cancer Biology, UCL Institute of Child Health, University College London, 30 Guilford Street, London, England.
Daniel A
DA
Morgenstern
Fyeza
F
Hasan
Sian
S
Gibson
Paul
P
Winyard
Neil J
NJ
Sebire
John
J
Anderson
D000911:Antibodies, Monoclonal / Q000378:metabolism; D000918:Antibody Specificity; D015153:Blotting, Western; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D018201:Nephroma, Mesoblastic / Q000378:metabolism; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000378:metabolism; D012516:Osteosarcoma / Q000378:metabolism; D051757:PAX5 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018335:Rhabdoid Tumor / Q000378:metabolism; D012208:Rhabdomyosarcoma / Q000378:metabolism; D012509:Sarcoma / Q000378:metabolism; D046888:Tissue Array Analysis; D009396:Wilms Tumor / Q000378:metabolism
D000911:Antibodies, Monoclonal; D009363:Neoplasm Proteins; D051757:PAX5 Transcription Factor; C497281:PAX5 protein, human; D012333:RNA, Messenger