PAX-8 as a Marker for Renal, Müllerian, and Thyroid Differentiation. A Comprehensive Study
A Ozcan, Y Ge, M Rust, G Hamilton, B Krishnan, LD Truong. The Methodist Hospital, Houston, TX; Baylor College of Medicine, Houston, TX; Gulhane Military Medical Academy and School of Medicine, Ankara, Turkey
Background: PAX-8 is a transcription factor that is essential in embryonic development of kidney, Müllerian organs, and thyroid . PAX-8 may also play role in tumor development in these organs. The diagnostic utility of PAX-8 has not been comprehensively studied.
Design: Formalin-fixed, paraffin-embedded tissue samples for non-neoplastic tissue (n=523 cases), primary neoplasms (n=498), and metastatic neoplasms (n=248) were subjected to immunostain for PAX-8.
Results: Non-neoplastic tissue: PAX-8 was constantly noted in glomerular parietal epithelial cells, renal collecting ductal cells; atrophic renal tubular epithelial cells regardless of nephronic segments; epithelial cells of endocervix, endometrium, and fallopian tube, seminal vesicle, epidydimis, and thyroid; and lymphoid cells. PAX-8 was not seen in the rest of tissue samples. Primary neoplasms: PAX-8 was expressed by 118/122 renal cell carcinomas (RCCs), 21/21 renal neoplasms other than RCC or transitional cell carcinoma, 132/139 Müllerian-type of neoplasms of ovary or endometrium, 20/20 thyroid follicular cell neoplasms, and 12/12 nephrogenic adenomas. PAX-8 was not seen in other neoplasms. Metastatic neoplasms: PAX-8 was expressed by 116/130 metastatic RCCs; 24/25 metastatic Müllerian tumors, and 3/3 metastatic thyroid follicular neoplasm. PAX-8 was not seen in other metastatic neoplasms. The staining was nuclear. Regardless of the diagnosis, the vast majority of cells were stained in the positive cases.
Conclusions: Routinely processed tissue is eminently suitable for optimal PAX-8 immunostain. PAX-8 is a very sensitive marker for non-neoplastic tissue, primary neoplasms, and metastatic neoplasms of renal, Müllerian, and thyroid origin.
Monday, March 22, 2010 1:00 PM
Poster Session II # 248, Monday Afternoon