[981] GATA 3 Immunohistochemical Expression in Primary and Metastatic Renal Cell Carcinomas

Enrico Munari, Nilda Gonzalez-Roibon, Sheila F Faraj, Alcides Chaux, Mohamad E Allaf, Rajni Sharma, George J Netto. Johns Hopkins Hospital, Baltimore, MD; Norte University, Asuncion, Paraguay

Background: GATA3 is a transcription factor involved in the development of several organs, including mammary gland, skin and kidney and has been suggested as a marker of urothelial differentiation and urothelial carcinoma including upper tract urothelial tumors. Its expression in primary renal tumors has not been fully determined. We evaluated the expression of GATA3 in a set of 177 renal carcinomas including 136 primary tumors and 41 unrelated metastatic clear cell renal cell carcinomas.
Design: Formalin-fixed paraffin-embedded tissues from primary clear-cell (71), papillary (14), chromophobe (33) and collecting duct (18) renal cell carcinomas and (41) unrelated metastatic clear cell renal cell carcinomas were retrieved from our surgical pathology archives and used to build 5 tissue microarrays. Paired tumor and non-neoplastic kidney were spotted 4 times each. GATA3 nuclear expression was evaluated using standard immunohistochemistry (GATA3: clone L50-823, BioCare Medical, CA). Intensity and extent (percentage) of expression were assessed in each spot. For each tumor, median extent of expression was calculated and the highest intensity of expression was recorded. Several cut off values (any positivity, >5% and >10%) were evaluated to indicate a positive GATA3 result.
Results: Median nuclear GATA3 expression was 0% (0%-16%). When considering any positivity, 2/136 (1.5%) cases of the primary renal cell carcinomas were positive for GATA3. These included one clear cell renal cell carcinoma (1%, 3+intensity) and one collecting duct carcinoma (16%, 2+ intensity). Only one case remained positive (0.7%) when using either 5% or 10% cut off values (collecting duct carcinoma). All 41 cases of metastatic clear cell renal cell carcinomas were negative for GATA3 expression (0%).
Conclusions: GATA3 is negative in renal cell carcinomas of papillary and chromophobe cell types and with a very rare exception clear cell, and collecting duct carcinomas. The findings are of great utility in excluding renal cell carcinoma as a primary site during interrogation of tumors of unknown primary. In addition, our findings further support the specifity of GATA3 labeling of urothelial carcinoma in the setting of difficult epithelial kidney tumors where the differential includes urothelial Vs renal cell carcinoma.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 157, Wednesday Afternoon


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