Ethnic and racial differences in prostate stromal estrogen receptor α

BACKGROUND: Prostate cancer incidence and mortality rates vary widely among individuals of different ethnic/racial groups. We identified a relationship between a subset of genes and race/ethnicity using gene expression profiling. Estrogen receptor alpha (ERalpha) was selected for confirmation due to its plausible biological role in cancer susceptibility. METHODS: Quantitative polymerase chain reaction (Q-PCR) was used to verify gene expression results. Protein levels of ERalpha were determined by quantitative immunohistochemistry in a large-scale tissue microarray study (n = 183). RESULTS: ERalpha was significantly higher in stroma of Hispanic and Asian men than in Caucasian (P < 0.0001) and African American men (P < 0.0002), who are at higher risk for prostate cancer. In addition, large differences were seen in Q-PCR levels of ERalpha in prostate tissues of organ donors 16-29 years old who had no evidence of cancer. CONCLUSIONS: ERalpha exhibits variable expression in men of difference racial/ethnic background. Understanding the molecular basis for these differences may form the basis for prostate cancer prevention strategies with widespread public health impact.