Delbert M. Shankel Departments of }1icrobiology and Biochemistry The University of Kansas Lawrence, Kansas 66045 Welcome to the "International Conference on Mecha. nisms of Antimutagen- esis and Anticarcinogenesis. " We are delighted that so many of you have chosen to attend this first meeting on this important topic. The significance of genetic changes in cells has been recognized for many years. The seminal observations of Henri in 1914 (UV), Muller in 1927 (X-rays), and Auerbach in 1946 (chemical agents) established the fact that physical and chemical agents which may be present in our environment are capable of producing profound changes in heredity. It is now well-estab- lished, of course, that such changes can result in the development of can- cer, produce hereditary birth defects, alter microorganisms to cause drug resistance, or other harmful (or even beneficial) changes; it is likely that the processes of mutagenesis and the intricate balance between muta- genesis and antimutagenesis are involved in aging, evolution, and other fundamental life processe8. Consequently, we hope and believe that assem- bling thi. s group of scientists to share current fundamental and applied research in these areas will lead to a better understanding of these proc- esses and to long-term benefits for society. As stated clearly by Garfield (4), "Almost every aspect of modern liv- ing exposes us to health risks.

Lifestyle, in any part of the world, is associated with the occurrence of major chronic diseases, including coronary heart disease, hypertension, and stroke; many distinct types of cancer; and adult onset diabetes (11,22,70,75). One important element of lifestyle is tobacco use, which appreciably increases the risk of a number of chronic diseases (21). Other lifestyle factors relate to nutritional traditions, alcohol use, and exercise (11,30,58,60,70,71). The underlying evidence is, in part, based on the evidence of specific diseases in relation to dietary habits in a given geographic region, as well as changes in such disease occurrences in migrant populations from a low risk to a high risk area, and vice versa (25,42). Populations that customarily consume fruits and vegetables and also whole grain cereal products generally have a lower risk of cardiovascular diseases and specific types of cancer than populations with a lower intake of such foods, everything else being equal (63). In the last few years, research has provided mechanistic explanations as to the reasons for the protective effects of specific foods. This paper will emphasize the mechanisms whereby cancer risks are reduced by dietary modification.