Gene expression profiles for monitoring radiation exposure

Previous demonstrations that the dose, dose rate, radiation quality, and elapsed time since ionising radiation exposure result in variations in the response of stress genes suggest that gene expression signatures may be informative markers of radiation exposure. Defining sets of genes that ate specific for different outcomes of interest will be key to such an approach. A generalised post-exposure prolile may identify exposed individuals within a population, while more specific fingerprints may reveal details of a radiation exposure. Changes in gene expression in human cell lines occur after as little as 0.02 Gy rays, and in peripheral blood lymphocytes alter as little as 0.2 Gy. Diverse genes are also elevated in vivo in mice 24 h after 0.2 Gy irradiation. Ongoing microarray analyses meanwhile continue to identify large numbers of potential biomarkers from varied irradiation protocols. Development of computation-intensive informatics analysis methods will be needed for management of the complex gene expression profiles resulting from such experiments. Although the preliminary data are encouraging, significant work remains before meaningful correlations with risk or practical assessment of exposure can be made by gene expression profiling.