Evaluation of Androgen, Estrogen (ERa and ERb), and Progesterone Receptor Expression in Human Prostate Cancer by Real-Time Quantitative Reverse Transcription-Polymerase Chain Reaction Assays

Steroid hormones can have profound effects on prostate tumor development making it important to define steroid receptor expression in prostate tissues. For this purpose, androgen receptor (AR) and estrogen receptor (ERa and ERb) expression was quantified in 12 clinically localized and 11 hormone-refractory sporadic prostate tumors, using real-time quantitative reverse transcription-PCR assays. To gain more insight into hormone-responsiveness, estrogen-regulated progesterone receptor (PGR) and androgen-regulated prostatic acid phosphatase (PAP) mRNA levels were also quantified. There is a decrease in expression of ERb in both clinically localized and hormone-refractory tumors relative to normal prostate tissues. Moreover, hormone-refractory tumors display a decreased expression of ERa and an increased expression of AR. There is a positive association between ERa, ERb, and PGR expression (P < 0.0001) and a negative association between AR and the androgen-regulated gene PAP expression in hormone-refractory tumors. Taken together, these data indicate that, although increased expression of the AR gene might play a key role in endocrine treatment failure, it cannot be considered as the sole actor of this unresolved dilemma, and abnormalities in ERa and/or ERb expression may also modulate the growth response of prostate cancer to hormone withdrawal. Our results also suggest that ERa and ERb expression status could be used to identify advanced prostate tumor patients who may respond to antiestrogen therapy.