Through an orderly sequence incorporating epidemiologic and laboratory research, human clinical/metabolic studies, and clinical intervention trials, the NCI develops and maintains cancer prevention and control programs that are directed toward the overall goal to reduce cancer incidence, morbidity, and mortality. Epidemiologic studies have shown correlations between consumption of numerous dietary constituents and cancer risk. Results of in vitro and animal studies have reinforced many of these epidemiologic associations and data from clinical/metabolic studies are being used to evaluate the relevance of these associations in humans. Although much remains to be learned about the influence of specific dietary constituents and dietary patterns on cancer risk, it is clear that diet can have a significant impact in cancer prevention and control. Investigations on the cellular and molecular effects of dietary constituents, as well as their metabolic and physiologic effects should provide better insight on the mechanisms of action of these dietary constituents. There also is a need to develop biomarkers of dietary intake that could be used to monitor compliance in intervention studies, as well as biomarkers as clinical trial endpoints that can be used to predict the emergence and progression of cancer. Working with other agencies and the private sector, the NCI will continue to design and implement information programs that translate the knowledge gained from these diet and cancer prevention studies to help Americans adopt dietary patterns that may reduce cancer risk. Continued emphasis will be placed on intervention programs targeted toward high-risk and underserved segments of the U.S. population in an effort to reduce the high incidence of cancers in these groups.