Cancer chemoprevention. Part 2: Hormones, nonclassic antioxidant natural agents, NSAIDs, and other agents.

This two-part series provides an up-to-date summary of the various chemopreventive agents currently in development and testing. Part 1, published in last month's issue, focused on the retinoids, such as all-trans-retinoic acid (ATRA [Vesanoid]), 9-cis-retinoic acid (9cRA), and isotretinoin (Accutane), and the carotenoids, such as beta-carotene and lycopene, and other "classic" antioxidants, such as vitamins E and C and selenium. This second part centers on hormonally mediated chemopreventives, such as tamoxifen (Nolvadex), finasteride (Proscar), oral contraceptives, and dehydroepiandrosterone (DHEA). A number of these agents have site-specific mechanisms of action and will be discussed as such. Also discussed in part 2 are various nonclassic antioxidant natural agents, including calcium, the polyphenols, the isothiocyanates, and genistein; nonsteroidal anti-inflammatory drugs (NSAIDS), such as aspirin and sulindac; difluoromethylornithine (DFMO [Eflornithine]); oltipraz; and N-acetylcysteine.