[1771] PAX-2 as a Renal and Mllerian Tumor Marker. A Comprehensive Study

QJ Zhai, A Ozcan, D Coffey, SS Shen, J Rehana, CR Hamilton, A Kundu, LD Truong. The Methodist Hospital, Houston, TX; Weill Medical College of Cornell University, New York, NY; Gulhane Military Medical Academy and School of Medicine, Ankara, Turkey

Background: PAX-2 is a transcription factor that is known to promote embryonic differentiation of central nervous system, kidney, and Mllerian organ. PAX-2 has been shown in renal neoplasms and Mllerian-type of neoplasms. However, the diagnostic utility of PAX-2 has not been comprehensively studied.
Design: Formalin-fixed, paraffin-embedded tissue samples for non-neoplastic tissue (443 cases), primary neoplasms (398), and metastatic neoplasms (91) were subjected to immunostain for PAX-2.
Results: PAX-2 was successfully detected as exclusive nuclear staining. For non-neoplastic tissue, PAX-2 was noted focally in glomerular visceral epithelial cells and in a subset of renal collecting ductal cells (89/89); diffusely in atrophic renal tubular epithelial cells (75/75); diffusely in normal endocervical, endometrial, and fallopian tubal cells (19/19), focally in regenerative bile duct epithelium (2/5); focally in lymphoid cell follicles (10/25). PAX-2 was not seen in the rest of tissue samples. For primary neoplasms, PAX-2 was expressed by 1/16 parathyroid adenomas, 1/1 endometrial polyp, 104/ 122 renal cell carcinomas (RCCs), 17/18 renal neoplasms other than RCC, and 9/50 Mllerian-type of neoplasms of ovary or endometrium. PAX-2 was not seen in other neoplasms including 20 transitional cell carcinomas. For metastatic neoplasm, PAX-2 was expressed by 71/95 metastatic RCCs, and 1/20 other metastatic tumors (metastatic endometrioid carcinoma).
Conclusions: Routinely processed tissue is eminently suitable for optimal PAX-2 immunostain. PAX-2 is a marker for Mllerian differentiation, but it is expressed in only a subset of Mllerian tumors. PAX-2 is a marker for renal differentiation and renal tubular atrophy. It is also a very sensitive and specific marker for both primary renal neoplasms and metastatic RCCs.
Category: Techniques

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 244, Wednesday Afternoon