[Biomarkers of effect and susceptibility to low doses of benzene]

Current occupational exposure levels to benzene are reduced by three orders of magnitudo (from ppm to ppb) as compared to the past. As benzene toxicity is related to its biotransformation and bioactivation pathways seem to be more active at lower exposure levels, observed effects could be higher than expected. Although the genetic polymorphisms of relevant and functional metabolic enzymes are implied in the modulation of either the risk of adverse effects [myeloperoxidase and NAD(P)H:quinone oxidoreductase] or of the biomarkers of internal dose (glutathione S-transferases M1-1, T1-1, A1-1), they are not appliable as biomarkers of susceptibility. Among biomarkers of early effect, only the longitudinal monitoring of blood cell count seems suitable to be applied in health surveillance protocols, whereas the use of biomarkers of genotoxic effect at current exposure levels is at the present not supported by literature data.