Distribution of prostasomes in neoplastic epithelial prostate cells

BACKGROUND. Prostasomes are a secretory product from the prostate. We aimed to investigate whether the distribution and amount of prostasomes in norma l prostate epithelium were influenced by the dedifferentiation occurring in adenocarcinomas of the human prostate gland. METHODS. Transurethrally resected material from 11 patients with prostatic carcinoma of various malignancy grades, material from two lymph node metast ases, and benign tissue from 10 total prostatectomies were subjected to imm unohistochemical staining, using a mouse monoclonal antibody against human prostasomes (mAb 78). RESULTS. Immunostaining of low-grade carcinoma was similar to that of norma l prostate gland which displayed a cytoplasmic granular staining of the api cal (luminal) aspects of the secretory epithelial cells. In moderately well and poorly differentiated adenocarcinoma, the amount of stained components decreased, and the staining pattern became more heterogeneous. In multilay ered glandular structures, the staining was concentrated at the lumen, leav ing most other cells negative. The neoplastic cells of lymph node metastase s of prostate carcinoma differed in amount and distribution of immunostaine d prostasomes. CONCLUSIONS. The antigen recognized in the prostasomes by mAb78 was express ed in benign prostate tissue, prostate cancer, and to a lesser degree in ly mph node metastases. There was a tendency towards decreased expression with increasing tumor grade. (C) 1999 Wiley-Liss, Inc.