[766] Estrogen Receptor-alpha (ERalpha) and beta (ERbeta) Expression in the Stroma Associated with Adenocarcinoma of the Prostate

LL Gellert, S Dahiya, J Melamed, L Chiriboga, D Hatcher, YR Li, SM Ho, YK Leung, P Lee. New York University, New York, NY; University of Cincinnati, Cincinnati, OH

Background: ERalpha and ERbeta are expressed in the stroma of prostatic adenocarcinoma. Recently there has been an increased interest in the role of tumor-associated stroma in prostate tumorigenesis, but little is known about the respective roles of ERalpha and ERbeta in prostate cancer. This study evaluated the expression of ERalpha and ERbeta in the tumor-associated stroma and the stroma surrounding benign prostate. The correlation between their expression and clinicopathological factors is also investigated.
Design: Immunohistochemical analysis with antibodies against ERalpha and ERbeta were used. Two sets of prostatic cancer cases are included. In the first set, whole tissue sections from 47 prostate cancer cases were studied to compare stromal ER levels in prostate cancer and benign prostate on the same slide. In the second study set, ER expression were studied in 200 samples of prostate cancer on a tissue microarray (TMA). The samples on TMA were stratified by clinicopathological factors. The levels of ER nuclear expression were scored as 0 negative, 1 weak, 2 moderate and 3 strong expression.
Results: The expression of both ERalpha and ERbeta is significantly lower in tumor-associated stroma (ERalpha: p <0.01; ERbeta: p=0.01) compared with stroma around benign glands. When stratified with clinicopathological factors, the level of ERalpha expression in tumor-associated stroma shows a positive correlation with Gleason score (r = 0.93, p<0.05). The expression of ERalpha is higher in prostate cancer with advanced tumor stage (p = 0.05). The level of ERbeta expression in tumor-associated stroma is decreased in older patients (p=0.01). No significant correlation between the expression of ERbeta in tumor-associated stroma and any other clinicopathological factors was detected.
Conclusions: This study demonstrated significant down-regulation of ERalpha and ERbeta expression in tumor-associated stroma of prostate cancer. However, ERalpha expression level in tumor-associated stroma shows a positive correlation with Gleason score and it is slightly increased in cases with advanced tumor stage. The level of ERbeta expression in tumor-associated stroma is decreased in older patients but not correlated with Gleason score or stage. These findings suggest that ERalpha and ERbeta plays different roles in the tumorigenesis and progression of prostate cancer.
Category: Genitourinary (including renal tumors)

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 99, Wednesday Morning