[845] Differential Steroid Hormone Expression in Renal Cell Carcinoma Subtypes

KK Newman, BY Wang, N Cetin, H Ye, X Zou, P Lee, J Melamed. New York University Langone Medical Center, New York, NY

Background: Recent studies have shown steroid hormone receptor positivity in renal cell carcinomas (RCC) specifically progesterone (PR) reactivity has been identified in renal oncocytoma and chromophobe renal cell carcinoma (CHR RCC), and estrogen (ER) and PR reactivity has been described in non-neoplastic renal tissue. Therefore, we have evaluated subsets of RCC to evaluate ER, PR and androgen receptor positivity and distribution, and whether these can provide diagnostic tools for renal cell carcinoma subtype differentiation.
Design: Archival formalin-fixed, paraffin-embedded renal tumor tissue from patients (n=95) who underwent nephrectomy over a 4- year period were combined into a tissue microarray and immunohistochemically stained for androgen (polyclonal rabbit antibody), ER (SP1) and PR (1E2). Immunoreactivity was scored semiquantitatively and results correlated with renal cell carcinoma subtype and clinicopathologic variables.
Results: The cohort included 73 cases of RCC (histological subtypes: 42 conventional clear cell type (CC RCC), 24 chromophobe,7 papillary), 15 oncocytoma, and 7 urothelial carcinoma. Immunoreactivity was: A) PR reactivity was found in 50% of CHR RCC, 100% of oncocytoma, 57% of urothelial cell carcinomas (staining was limited to non-neoplastic urothelium). B) None of the tumors or non-neoplastic components displayed ER positivity. C) Androgen positivity was found in 45% of CC RCC and 50%CHR RCC. Reactivity in CC RCC varied from weak to strong in 10-75% of nuclei. Androgen positivity in CHR RCC was weak to moderate in 10-20% of nuclei.
Conclusions: This study demonstrates a differential steroid hormone reactivity (PR and AR) in RCC subtypes. PR staining does not differentiate oncocytoma from CHR RCC however may be useful to differentiate them from other subtypes of RCC. Androgen receptor reactivity in CC and CHR RCC and in none of the oncocytomas or papillary RCC suggests inclusion in a panel of markers used to separate CHR RCC from oncocytoma. It also raises the possibility that androgen modulation may play some role in CC RCC and should be further studied for its therapeutic implications in metastatic disease.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 77, Tuesday Morning