CHARACTERISTICS OF NONNEOPLASTIC HUMAN PROSTATE TISSUE TRANSPLANTED INTO NUDE-MICE

BACKGROUND. Prostate tumors are characterized by sex hormone-associate d growth and mesenchymal-epithelial interactions. This study was condu cted to establish an ex vivo system where human prostate tissue could be maintained for a certain period under conditions resembling the in vivo situation in man to provide an experimental tool for investigatio n of prostate disease. METHODS. Human prostate tissues (peripheral zon e and transition zone) obtained by total cystectomy were transplanted into the subcutis of male KSN nude mice for up to 24 weeks without exo genous hormonal manipulation. RESULTS. Transplants could be maintained , and although they showed several histological alterations, such as c ystic dilation, basal-cell hyperplasia, and squamous-cell metaplasia, many retained a nearly normal appearance for the entire 24-week durati on. Immunohistochemically, androgen receptors were strongly positive i n the nuclei of glandular epithelial cells. Prostate-specific antigen (PSA) and prostatic acid phosphate (PAP) (both from DAKO, Glostrup, De nmark), were also expressed in the cytoplasm. The proportion of cells expressing proliferating cell nuclear antigen (PCNA) was not related t o the period of transplantation and did not differ between the periphe ral and transition zones. CONCLUSIONS. The results clearly demonstrate that human prostate tissues transplanted into nude mice can maintain their morphological and biological characteristics for up to 24 weeks. This provides a simple and useful tool for basic research into human prostate neoplasia. (C) 1998 Wiley-Liss, Inc.