Prostatic cancer induced in MRC rats by N-nitrosobis(2-oxopropyl)-amine and N-nitrosobis(2-hydroxypropyl)amine.

Weekly intragastric treatment with N-nitrosobis(2-oxopropyl)amine or N-nitrosobis(2-hydroxypropyl)amine induced hyperplastic, preneoplastic and neoplastic prostatic changes in greater than 80% of MRC rats. The lesions initially appeared as focal or multifocal proliferations of alveolar epithelium in a cribriform pattern which, in all but one case, underwent progressive changes, often tending toward squamous cell formation. Tumors, found primarily in the ventral prostate, demonstrated various degrees of differentiation and invasive growth. A few neoplasms developed in the seminal vesicles; however all were of a glandular type. The sequential alteration of induced lesions is described and the possible reasons for the squamous cell character of most tumors discussed. Prostatic cancer induction by systemic application of specific nitrosamines could provide a unique tool for investigating important aspects of the disease.