Application of ionizing radiation in studies of biomarkers of individual susceptibility

Human biomonitoring, as a tool to identify health risk from environmental exposures, has gained increasing interest especially in the areas of cancer risk assessment and diseases treatment. Chromosome aberrations resulting from direct DNA breakage or from inhibition of DNA repair or synthesis, measured in peripheral blood lymphocytes, have been used successfully in the assessment of health risk associated to environmental genotoxic exposures. A faster but sensitive and reliable method for detection of DNA damage, or DNA repair capacity, might be crucial to many fields from molecular epidemiology and toxicology to preventive and clinical medicine. There are reports that results of DNA measures with the use of single cell gel electrophoresis (SCGE) correlate, on the one hand, with physical measures of genotoxins, and on the other hand, with cytogenetic damage that is a biomarker associated to the alteration of the health risk. This review is based on studies in which exposure to radiation was applied as a challenging treatment and DNA damage induced and repaired was analyzed with the use of the alkaline version of SCGE assay. Results from studies on susceptibilities and repair competence carried out in various groups of exposed workers, controls, and cancer patients (more than 700 donors) show variability between donors both in a response to challenging treatment and in the efficiency of repair process. Influences of the occupational exposures and factors depending on genotypes or life style on cellular capacities are observed. Discussed results suggest that study in vitro with the challenging cells by radiation exposure and measuring, with the SCGE assay, the DNA damage before and after repair, may develop a good biomarker of the individual susceptibility to various genotoxins and exposures (environmental, occupational, therapeutic). Such a biomarker may have a potential use in a molecular epidemiology and preclinical identification. (author)