AB - Cancer chemoprevention is defined as the use of specific chemical compounds to prevent, inhibit or reverse carcinogenesis.
Chemopreventive intervention can occur throughout carcinogenesis.
Chemopreventive drugs are usually administered chronically and are expected to have low toxicity. A variety of mechanisms explain the actions of chemopreventive compounds including modification of carcinogen activation and cellular uptake, inhibition of aberrant signal transduction, induction of apoptosis and inhibition of angiogenesis. As our understanding of carcinogenesis has developed, more specific pharmacologic targets are being selected, e.g. retinoid receptors or cyclo-oxygenases. Recent examples include the striking effectiveness of tamoxifen in reducing the risk of breast cancer in women at high risk. The future development of predictive risk models that take into account gene-environment interactions will be of considerable value in deciding on specific chemopreventive interventions in those at increased risk by virtue of life style or occupational exposures.