A new prostatic cancer model: systemic induction of prostatic cancer in rats by a nitrosamine.

Weekly intragastric application of N-nitrosobis(2-oxopropyl) amine (BOP) at a dose of 10 mg/kg body wt induced prostatic cancer in 5 out of 15 MRC rats. Hyperplasia and metaplasia of the prostatic gland were found in 13 rats with or without cancer. All tumors had developed in the dorsal lobe, had reached a size of up to 20 mm and were invasive. Distant metastases were not observed. Although hyperplastic lesion were of a glandular type, all carcinomas had squamous cell character. All cases of prostatic cancer were associated with papillomas or carcinomas of the urethral epithelium, which had initially developed in the colliculus seminalis. The induction of prostatic cancer for the first time by a systemic application by a nitrosamine provides a promising model for understanding basic principals of prostatic cancer.