Approaches to cancer prevention based on an understanding of N-nitrosamine carcinogenesis

Abstract. Understanding carcinogenesis is critical for development of rational ap-proaches to cancer prevention. This paper uses Mnitrosamine carcinogenesis as an example. MNitrosamines are a large group of potent carcinogens. Approximately 300 different N-nitrosamines are carcinogenic. At least 30 animal species are responsive to their effects. There is little doubt that humans exposed to sufficient amounts of Mnitrosamines would also be susceptible to their carcinogenic effects. Human expo-sure to preformed Mnitrosamines occurs through the diet, in certain occupational settings, and through the use of tobacco products, cosmetics, pharmaceutical prod-ucts, and agricultural chemicals. Diminishing human exposure to these carcinogens is one approach to prevention of cancer, and this has been accomplished in many instances, although exposure to N-nitrosamines in tobacco products is still unaccept-ably high. Human exposure to N-nitrosamines also occurs by nitrosation of amines in the body, via their acid or bacterial catalyzed reaction with nitrite, or by reaction with products of nitric oxide generated during inflammation or infection. A second ap-proach toward prevention of N-nitrosamine carcinogenesis is inhibition of this endog