The Expression of GPR 30, a G Protein-Coupled Receptor, in Prostate Cancer
M Zhang, HM Lam, MQ Yu, JH Wang, B Ouyang, S Jain, G Daniels, V Reuter, A Gopalan, I Osman, P Lee, SM Ho. New York Univeristy School of Medicine, New York, NY; University of Cincinnati, Cincinnati, OH; Memorial Sloan Kettering Cancer Center, New York, NY
Background: The role of estrogen and its receptors in prostate cancer has now been recognized. There are distinct expressions and functions of estrogen receptors ERα and ERβ in prostate cancer epithelial cells and in tumor associated stromal cells. In this study, we determined the expression of G protein-coupled receptor for E2, GPR30. Our group demonstrated that GPR30 was down-regulated in prostate cancer when compared to the normal tissue by RT-PCR, which is in concordance with the public microarray database Oncomine. Herein we examined the expression of GPR30 protein in prostate cancer in relation to clinicopathological features.
Design: Immunohistochemistry was performed using antibody against GPR30 to characterize its expression pattern in prostate cancer to compare GPR30 levels in prostate cancer with adjacent benign prostate using tissue microarray (TMA) (n= 199), to correlate with various clinocopathological parameters. The levels of GRP30 expression, membranous, cytoplasmic or stromal stain, were scored semi-quantitatively; 0: negative, 1+: weak, 2+: moderate and 3+: strong expression.
Results: We observed distinct patterns of GPR30 expression for membranous and cytoplasmic stain in cancer epithelial cells, as well as stromal cells. The membranous stain is decreased in cancer cells in 40 of 190 (21%) cancer cases compared to 29 of 69 (42%) cases in benign prostate. When correlated with clinicopathological parameters, the level of GPR30 expression in the membrane of tumor cells was significantly lower in prostate cancer with advanced tumor grade and stages (p<0.05). Strikingly, the stromal GPR30 expression is significantly decreased in cancer from 68 of 69 benign cases (98.5%) to 19 of 190 (10%) of cancer cases with an average 19% cells in benign stromal cells and 4% in cancer stromal cells (p<0.05). These results correlated with the growth inhibitory effect of GPR30 on prostate cancer cells.
Conclusions: This study demonstrates significant down-regulation of GPR30 expression in the membrane of cancer epithelial cells and stroma of prostate cancer. These results strongly suggest a role of GPR30 in high grade and advanced stage prostate cancer.
Category: Genitourinary (including renal tumors)
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 120, Wednesday Afternoon