Acetylation as an indicator of risk.

Aromatic amine acetylation has been recognized for many years as an important metabolic polymorphism in humans because of its relationship to disease. This system serves as a model in risk assessment because of its role in drug and carcinogen activation and detoxification and because of the case with which it is measured. However, possible interactions of NAT1-NAT2 phenotypes or genotypes illustrate the complexity of xenobiotic metabolism pathways. Moreover, the use of such information for risk assessment is further complicated by the association of the rapid phenotype with increased risk in colon cancer and the slow phenotype with increased risk in urinary bladder cancer. Before this biomarker can be effectively utilized as a significant predictor of individual risk, it will be necessary to identify specific sources of aromatic amine exposure and to characterize further the substrate specificity of NAT1 and NAT2 in relation to the multiplicity of enzyme variants occurring in human populations.