Steroid hormone receptors and endocrine response of prostatic carcinoma.
In this study 63 open prostatectomies were performed and studied for steroid receptor content. There were 23 prostatic carcinoma (PC) and 40 benign prostatic hyperplasia (BPH). All grades and stages of cancer were represented. Androgen (AR), estrogen (ER), and progesterone (PR) receptors were assayed in the same cytosols prepared from the BPH and PC patients. Nuclear AR was also assayed in some specimens from PC patients. All receptor assays were performed before therapy was given to PC patients. Two distinct binding sites for estrogen with two different affinities and capacities were found in the cytosol fractions of BPH and PC tissues. The mean values for the high affinity site (Kd approximately 0.1 nM) were 4-fold greater in PC than BPH (P less than 0.05), while the mean values for the low affinity estrogen binding site (Kd greater than 2 nM) were slightly lower in PC than BPH. There was no significant difference in PR content between PC and BPH. AR content in PC was approximately 2-fold greater than BPH (P less than 0.05). Higher amounts of high affinity estrogen binding sites and/or high androgen receptor content in tumor tissues appear to be potential markers to predict the response of PC patients to endocrine therapy. Simultaneous measurement of nuclear AR with cytosolic AR increased the predictability of endocrine response.