Comparison of dihydrotestosterone levels in prostatic cancer metastases and primary prostate cancer.

Dihydrotestosterone (DHT) concentration, a marker for biochemical differentiation and possible clonal origin of prostate tumors, was measured in cancer present in lymph nodes (LN) from patients with untreated metastatic prostate cancer and compared to levels in untreated primary prostate cancer. The mean DHT of 2.23 ng/g in LN (S.E. = 0.28, N = 22) was significantly less (P less than .001) than the mean DHT of 4.8 ng/g in primary cancer (S.E. = 0.52, N = 20). Since primary prostate cancer may be admixed with stromal tissue, while lymph node represents pure epithelial cell tumor, we chose for this comparison only the 20 prostate cancer tissues that were judged by our pathologist to contain 90% or more epithelial cell tumor. Using this selection criteria, we found that prostate stroma, which has an average DHT concentration 1.18 times higher than prostate epithelia, would have an insignificant effect on primary prostate tumor DHT concentration. These data suggest that the decreased DHT in prostate tumor cells present in LN metastases may be a marker for a clone of cells with metastatic potential. These findings are consistent with previous reports from this laboratory indicating that DHT concentration less than 2.4 ng/g in primary prostate cancer is a predictor of a reduced disease-free interval following androgen blockade in advanced prostate cancer.