Genotyping in Urine: An Interesting Tool for Epidemiological Studies

Many enzymes involved in the biotransformation of xenobiotics have been shown to be genetically polymorphic, as reviewed recently (1). The rapidly growing list of polymorphic genes coding for xenobiotic-metabolizing enzymes includes various cytochrome P450s, flavin monooxygenases, epoxide hydrolase, NAD(P)H:quinone oxidoreductase, UDP-glucuronosyltransferases, N-acetyltransferases, glutathione-S-transferases, and paraoxonase. Among these are enzymes of great importance in the field of environmental and occupational toxicology; therefore, an effort should be made to develop valid genotyping techniques easily applicable on a large scale, e.g., in the framework of epidemiological studies in industrial settings. Although in clinical practice genotyping is usually carried out on DNA extracted from white blood cells, the necessity of blood sampling probably contributes to limit the use of genotyping techniques in large cohort studies. The principal objective of this study is, therefore, to validate a reliable and robust protocol aimed to obtain, from urinary samples, a biological material on which molecular biology techniques such as restriction fragment length polymorphism (RFLP) analysis could be applied to determine the genotypic status of individuals. Indeed, in occupational and environmental medicine urine is a biological medium that is more easily sampled than blood and is very often obtained for biomonitoring purposes.