Prostate cancer chemoprevention by green tea.

Prostate cancer (PCA) is one of the most invasive cancers and the second leading cause of cancer-related deaths among males in the United States. According to an estimate, 1 of every 11 American men will eventually develop PCA. One way to reduce the occurrence of cancer is through chemoprevention. PCA represents an excellent candidate disease for chemoprevention because it is typically diagnosed in men over 50 years of age, and therefore even a modest delay in neoplastic development achieved through pharmacological or nutritional intervention could result in a substantial reduction in the incidence of clinically detectable disease. The ideal agent(s) suitable for chemoprevention of PCA should be the one(s) that has proven efficacy in the laboratory experiments on one hand, and also possesses proven epidemiological basis on the other hand. This review attempts to address the issue of possible uses of tea, especially green tea, for the prevention of PCA. We are providing the experimental as well as the epidemiological basis for this possibility. Many laboratory experiments conducted in cell culture systems and in animal models have shown the usefulness of green tea, and the polyphenols present therein, against PCA. The epidemiological basis for this possibility is twofold. First, some epidemiological observations have suggested that people who consume tea regularly have a lower risk of PCA-related deaths. Second, the incidence of PCA in China, a population that consumes green tea on a regular basis, is lowest in the world.