GENISTEIN ALTERS THE ONTOGENY OF MAMMARY-GLAND DEVELOPMENT AND PROTECTS AGAINST CHEMICALLY-INDUCED MAMMARY-CANCER IN RATS

Breast cancer is the most common cancer in US females and is the secon d leading cause of cancer death among women. By contrast, Asian women consuming a traditional diet high in soy products have a relatively lo w incidence of breast cancer. Asians who emigrate to the United States and adopt a Western diet lose this protection. Soy-based diets are hi gh in phytoestrogens, and one of these components is genistein. Using the dimethylbenz(a)anthracene (DMBA) mammary cancer rodent model, we h ave investigated the breast cancer protective potential of genisteln. Our results demonstrate that neonatal and prepubertal genistein treatm ents altered the ontogeny of the mammary gland and rendered the adult animals less susceptible to chemically-induced mammary cancer. Neonata l genistein treatment did not significantly alter the rate of formatio n and persistence of DMBA-DNA adducts in the mammary gland. While high concentrations of genistein during the neonatal period caused adverse effects on ovarian follicular development, prepubertal genistein trea tment did not appear to be toxic in either the female reproductive tra ct or the endocrine system.