There are few options for treating
hormone-refractory
prostate cancer (PC). Various studies indicate that
luteinizing hormone-releasing hormone (
LHRH) agonists may have a direct inhibitory effect on prostate
tumors mediated by specific
LHRH receptors. One study evaluated
LHRH receptors in
hormone-dependent PC tissue, but no data have thus far been obtained on the presence of
LHRH receptors in
benign prostatic hyperplasia (BPH) and especially
hormone-refractory PC in patients. Thus, it is not yet clear whether
LHRH receptors indicate
tumor-related differentiation or even
hormone-refractory dedifferentiation or are likewise associated with BPH. The aim of this study was to determine the rate of
LHRH receptor mRNA expression in BPH and in primary, potentially
androgen-dependent and in
hormone-refractory PC with
clinical progression. Multiplex reverse transcription-PCR was used to simultaneously detect the expression of
mRNA for
LHRH receptors and
beta-actin in 48 patients with BPH, 14 with a primary, possibly
hormone-dependent, prostate
carcinoma (PPC), and 18 with a
hormone-refractory prostate
carcinoma (HRPC). Sixteen of 18 samples with HRPC showed intact
RNA and expressed
mRNA for
LHRH receptors (100%). However, the
RNA-intact PPC and BPH showed significantly lower expression of
mRNA for
LHRH receptors (46.2 and 55.3%, respectively; variance analysis: P = 0.0017). The significantly higher expression of
mRNA for
LHRH receptors in HRPC indicates that therapeutic concepts should be developed that target this site of action. In addition to possible direct effects of
LHRH agonists or antagonists demonstrated previously in vitro, it seems useful to apply targeted cytotoxic
LHRH analogues or
monoclonal antibodies.