- There is extensive and consistent evidence that high intake of fruit and vegetables is associated with decreased risk of many types of cancers. Thus, it is widely accepted that diet changes are a powerful tool for cancer prevention and for inhibition of cancer progression. The growing interest in the role of the tomato carotenoid, lycopene, in cancer prevention and treatment, combined with the hypothesis that a single micronutrient cannot replace the power of a diet rich in fruit and vegetables, are the basis for this review. The mechanism of lycopene function in cancer cells involves interference in the mitogenic pathway of IGF‐I and slowdown of cell cycle progression. The recent observation that high plasma IGF‐I levels is an important risk factor for breast and prostate cancer, similar to the role of cholesterol in cardiovascular diseases, further places dietary intervention in the focus of anticancer research. Moreover, as suggested by our studies and those of others, it is possible that derivatives of lycopene and other carotenoids, not only the native molecules themselves, are the active compounds, since it was found that such derivatives can interact with members of the nuclear receptor family. If an active lycopene derivative will be identified by this approach, it can be used as a parent compound for the development of a new series of potent anticancer drugs based on natural dietary ingredients. Drug Dev. Res. 50:448–456, 2000. © 2000 Wiley‐Liss, Inc.