Prostatic carcinogenesis evoked by cellular interaction.

Inoculation of tumorigenic prostatic stroma and nontumorigenic prostatic epithelia into the subcutaneous space of syngeneic rats induced the development of carcinosarcoma. The induced tumors, which were composed of a mixture of adenocarcinoma and fibrosarcoma, were androgen responsive. This model offers a novel mechanism for prostatic carcinogenesis in which prostatic fibroblasts determine epithelial growth, androgen responsiveness, and tumorigenicity. Our results emphasize the potential importance of an epigenetic pathway in prostatic carcinogenesis.