8-Hydroxy-2'-deoxyguanosine as a marker of oxidative DNA damage related to occupational and environmental exposures.

Oxidative DNA damage is considered to play an important role in pathophysiological processes, ageing and cancer. So far major interest has been on measuring 8-hydroxy-2'-deoxyguanosine (8-OHdG), the preferred methods relying on HPLC or GC-mass spectrometry. The high biological relevance of 8-OHdG is due to its ability to induce G-->T transversions, which are among the most frequent somatic mutations found in human cancers. Effects of workplace exposures on the level of white blood cell 8-OHdG or urinary 8-OHdG have been reported with controversial results. Exposures examined include asbestos, azo-dyes, benzene, fine particulate matter (PM(2.5)), glassworks, polycyclic aromatic hydrocarbons (PAHs), rubber manufacturing, silica, metals, styrene, toluene and xylenes. The available data indicate that there is still a lack of well established dose-response relations between occupational or environmental exposures and the induction of 8-OHdG. Smoking has been most consistently identified as a confounder for 8-OHdG, but various occupational studies did not reveal higher levels of 8-OHdG in smokers. Despite the conflicting results, the reported studies show promise for 8-OHdG as a biomarker of oxidative stress associated with chemical exposure. However, there are critical aspects related to the analytical challenge, artifactual production of 8-OHdG, inter- and intra-individual variation, confounding factors and inter-laboratory differences, implying that further work is needed to reach a consensus on the background level of 8-OHdG.