Evaluation of 32P - post labelling as a suitable detection technique for biomonitoring of human DNA adducts

DNA adducts generated by carcinogenic chemicals reflects human exposure and DNA adducts are directly related to tumour formation. For detection of DNA adducts the most widely used methods include mass spectroscopy, fluorescence spectroscopy, immuno assays and 32P-post labelling. Among them, the 32P-post labelling method meets most of the requirements needed to be applicable in human exposure settings, and, therefore, it seems to be the most appropriate for biomonitoring of human DNA adducts. This technique has emerged as a major method to detect DNA adducts induced by structurally diverse carcinogens and other DNA lesions (i.e. apurinic sites in DNA, oxidative damage to DNA, UV-induced photodimers). The method comprises enzymatic degradation of DNA to deoxynucleotides, enrichment of adducts, 5'-32P- labelling, adduct separation by TLC (or HPLC), and detection and quantitation of adducts. The article presents the individual 32P- post labelling techniques (standard procedure, enrichment methods) and a critical evaluation of these assays, besides reviewing the applications of the method to different DNA modifications, and its utilization in human biomonitoring studies to detect damage from occupational exposure to carcinogens, and also from environmental (i.e. non-occupational) exposures. (author)