Albumin and hemoglobin adducts of benzo[a]pyrene in humans—Analytical methods, exposure assessment, and recommendations for future directions

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in our environment and can cause cancer. Exposure to PAHs can be assessed by protein adduct dosimetry using benzo[a]pyrene (B[a]P) as a model compound. We present an overview of analytical methods to detect B[a]P- derived protein adducts in humans, their uses in exposure assessment, and recommendations for future research. Two major methodologies, enzyme-linked immunosorbent assay (ELISA) and chemical-specific assays, could be traced in the literature but there remains limitations with both assays. ELISA is nonspecific due to cross-reactivity of the antibody with other PAHs and results are better interpreted in terms of PAH exposure. ELISA is unable to distinguish between exposed and nonexposed persons in the majority of studies. Adduct concentrations are higher by several orders of magnitude compared to those determined by chemical-specific methods. The latter methods mostly analyzed protein adducts derived by (+)-anti-B[a]P-diol epoxide. For this purpose, gas or liquid chromatography in combination with mass spectrometry or fluorescence detection were used. However, the prevalence of positive samples remained low when chemical- specific assays were used mainly due to the lack of sensitivity. Overall, data on B[a]P-derived protein adducts in humans remain inconclusive. Future research should focus on the development and standardization of a sensitive and specific method for B[a]P-derived protein adducts prior to its use in field studies. Finally, exposures of B[a]P at the workplace and via diet, a major route of exposure of the general population, can be studied. The results will contribute to the understanding of B[a]P-induced cancer and will allow for health preventive measures.