Carcinogen DNA and Protein Adducts as Biomarkers of Human Exposure in Environmental Cancer Epidemiology

Carcinogen DNA and protein adducts promise to provide a more objective measure of human exposure to environmental carcinogens than can be obtained by questionnaire data or environmental measurements. The adducts represent an integration of exposure, absorption, distribution, metabolism, DNA repair, and cell turnover, and thus provide a measure of biologically effective dose; the fact that DNA adducts are involved in the carcinogenic process means such a measure may be more relevant than exposure measures based on ambient levels of a given carcinogen. This approach has been successfully applied to situations where accurate questionnaire data on exposure are difficult to obtain (e.g., for the dietary carcinogens aflatoxins and heterocyclic amines, aromatic amine exposure via environmental tobacco smoke, etc.). Despite the promise of carcinogen DNA and protein adducts, there are a number of issues that must be addressed, including sensitivity, specificity, temporal relationship between exposure and disease, and their mechanistic role in the process of carcinogenesis. This information is a necessary prerequisite to the successful application of these biomarkers into appropriately designed epidemiological studies.