Biomarkers of exposure, sensitivity and disease

Purpose: This review is to evaluate the use of biomarkers as an indication of past exposure to radiation or other environmental insults, individual se nsitivity and risk for the development of late occurring disease. Overview: Biomarkers can be subdivided depending an their applications. Mar kers of exposure and dose can be used to reconstruct and predict past accid ental or occupational exposures when limited or no physical measurements we re available. Markers of risk or susceptibility can help identify sensitivi ty individuals that are at increased risk for development of spontaneous di sease and may help predict the increased risk in sensitive individuals asso ciated with environmental or therapeutic radiation exposures. Markers of di sease represent the initial cellular or molecular changes that occur during disease development. Each of these types of biomarkers serves a unique pur pose. Outline: This paper concentrates on biomarkers of dose and exposure and pro vides a brief review of biomarkers of sensitivity and disease. The review o f biomarkers of dose and exposure will demonstrate the usefulness of biomar kers in evaluation of physical factors associated with radiation exposure, such as LET, dose-rate and dose distribution. It will also evaluate the use of biomarkers to establish relationships that exist between exposure param eters such as energy deposition, environmental concentration of radioactive materials, cc traversals and dose. In addition, the importance of biologic al factors on the magnitude of the biomarker response will be reviewed. Som e of the factors evaluated will be the influence of species, tissue, cell t ypes and genetic background. The review will demonstrate that markers of se nsitivity and disease often have little usefulness in dose-reconstruction a nd, by the same token, many markers of dose or exposure may not be applicab le for prediction of sensitivity or risk.