ABSTRACT
Induction of mammary cancer after application of an aromatic carcinogen to a site remote from the breast was first observed by J. Maisin and M. L. Coolen in 1936. There is evidence from genetic crosses in various combinations that rat mammary carcinogenesis is regulated by multiple genes, with quantitative traits. Analysis of genetic changes is essential to clarify the mechanisms involved in mammary carcinogenesis as well as providing clues for new prevention and therapeutic measures. Genetic factors also determine the rate of tumor induction by chemical carcinogens to a large extent. Hormones are known to be important not only in cancer of the mammary gland but also in carcinogenesis of the uterus/cervix and of the prostate gland. The Huggins method, with gavage of a single or several doses of test chemicals in oil into a mammary cancer-susceptible strain of rats, followed by a high-fat diet, may be the most efficient and appropriate method for examination of mammary carcinogenicity.
