Both environmental and genetic factors are believed to contribute to the multistage process that results in carcinogenesis. Therefore, determining the health risks associated with exposure to known and suspected carcinogenic chemicals is essential for informed decision-making by regulatory agencies. Dr. Roger W. Giese and colleagues at Northeastern University developed sensitive and specific techniques for measuring polycyclic aromatic hydrocarbon (PAH)-DNA adducts, a class of DNA adducts associated with exposure to constituents of diesel emissions and other combustion products. Mass spectrometry (MS) is used in this study to measure DNA adducts and linked to a chromatographic system, such as gas chromatography (GC). Mass spectrometry is a powerful technique because it can distinguish among different carcinogen-DNA adducts, and it provides information about chemical structure. In this study, the investigators set out to develop derivatives of PAH-DNA adducts that are better than those that currently exist, and to improve the overall sensitivity of the MS technique.