DNA damage as an intermediate biomarker in intervention studies.

The development of sensitive assays for measurement of DNA damage in humans has great potential for enhancing intervention studies. Methods for DNA adduct measurement include immunoassays, [32p] postlabeling, high-performance liquid chromatography with fluorescence or electrochemical detection, and gas chromatography/mass spectroscopy. It is now well established that DNA adducts are a marker of exposure to various environmental, lifestyle, or occupational chemical carcinogens. Our own studies concentrate on immunologic detection of adducts by enzyme-linked immunosorbent assay (ELISA) of isolated DNA or quantitative immunohistochemical analysis of intact cells. Polycyclic aromatic hydrocarbon (PAH)-DNA adducts are elevated in blood cells of foundry and coke oven workers, individuals with high levels of exposure to environmental air pollution, and smokers. The study in smokers also found an inverse relationship between serum antioxidants and PAH-DNA, and is the basis for an ongoing antioxidant intervention. DNA adducts of PAH and 4-aminobiphenyl and oxidative DNA damage (8-oxo-deoxyguanosine) are being measured in blood mononuclear cells and exfoliated oral and bladder cells from subjects on antioxidants or placebo. Data on published intervention studies investigating oxidative damage and general aromatic DNA adducts measured by postlabeling are also summarized. These studies have already demonstrated that DNA adducts can be modulated by interventions and suggest that they can provide important mechanistic information in support of larger scale studies.