Characteristics of nonneoplastic human prostate tissue transplanted into nude mice

Prostate tumors are characterized by sex hormone-associated growth and mesenchymal-epithelial interactions. This study was conducted 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 investigation of prostate disease.

Human prostate tissues (peripheral zone and transition zone) obtained by total cystectomy were transplanted into the subcutis of male KSN nude mice for up to 24 weeks without exogenous hormonal manipulation.

Transplants could be maintained, and although they showed several histological alterations, such as cystic dilation, basal-cell hyperplasia, and squamous-cell metaplasia, many retained a nearly normal appearance for the entire 24-week duration. Immunohistochemically, androgen receptors were strongly positive in the nuclei of glandular epithelial cells. Prostate-specific antigen (PSA) and prostatic acid phosphate (PAP) (both from DAKO, Glostrup, Denmark), were also expressed in the cytoplasm. The proportion of cells expressing proliferating cell nuclear antigen (PCNA) was not related to the period of transplantation and did not differ between the peripheral and transition zones.

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.