Certain aspects of molecular endocrinology that relate to the influence ofdietary factors on the pathogenesis of prostate cancer

Isoflavonoids, flavonoids and lignans are natural oestrogenic compounds der ived from soya, tea, fruits and vegetables and they have been proposed as c hemopreventive agents in Asian men, in whom the incidence of prostate cance r is much lower than in men from the West. In addition to their weak oestro genic activity, oestrogen antagonistic activity has also been described for some of these compounds. Furthermore, the lignan, enterolactone and the so ya-derived isoflavone genistein are inhibitors of several steroid metabolis ing enzymes, such as aromatase, 5 alpha-reductase and 17 beta-hydroxysteroi d dehydrogenase. Genistein is a potent inhibitor of tyrosine kinases and al ong with flavonoids such as kaempferol and apigenin is also an inhibitor of topoisomerases I and II, enzymes which are crucial to cellular proliferati on. Genistein is also an inhibitor of angiogenesis and many experimental in vivo and in vitro models, including those for prostate cancer, are growth inhibited by isoflavonoids, flavonoids and lignans. It is estimated that th e traditionally eating Japanese male consumes approximately 20 mg of isofla vones per day, whereas for Western men, the daily consumption would be less than 1 mg/day. This is reflected in a high mean plasma concentration of ge nistein (180 ng/ml, n = 72) in Japanese men, compared to a level of <10 ng/ ml for Western males.