DNA markers of oxidative processes in vivo: relevance to carcinogenesis and anticarcinogenesis.

Understanding endogenous mechanisms of carcinogenesis through measuring oxidative markers has advanced greatly in the past decade, paralleling similar achievements in exogenous carcinogenesis through measurements of DNA-adduct markers. Understanding the mechanisms of genesis, metabolism, and physiological properties of the products of oxidative stress is essential in determining products that are specific molecular markers. Measurement technology allows sensitive detection, monitoring, and quantitation of oxidative DNA markers both locally in tissue and systemically in body fluids. Both approaches can be used to assess oxidative stress. Although measurement of markers of oxidative stress relevant to carcinogenesis is at an early stage of development, this approach will probably become an integral part of early diagnostics and the assessment of tumor metabolism. For comprehensive understanding of endogenous carcinogenesis, oxidative markers of protein and lipid damage are also necessary. A larger and perhaps more important application of oxidative markers is in anticarcinogenesis, particularly chemoprevention. Because urinary markers are a noninvasive methodology, they are especially appropriate for assessing and indexing the anticarcinogenic potential of diets and foods from modulation of the rate of DNA damage, which may be correlated with mutagenic and, ultimately, carcinogenic potential.