Monitoring very low dose radiation damage in DNA using "field-friendly" biomarkers

The retrospective assessment of radiation exposures using quantitative biomarkers related to dose is well established for the purpose of biological dosimetry. Among the range of candidate biomarkers that could be used to estimate the dose received by a person, DNA damage-associated markers play a prominent role. One of the hallmarks of ionising radiation, which distinguishes it from many other environmentally relevant agents, is its ability to induce DNA double-strand breaks (DSB) at sites of ionisation clusters along the particle track. These frequently give rise to gross chromosomal rearrangements such as translocations, dicentrics and acentric fragments, the latter of which may form micronuclei in daughter cells. These chromosomal aberrations, and especially dicentrics, are regarded as the “gold standard” for radiation biodosimetry, and a lot of effort has gone into the development of ISO standards, automation and networking to enable robust and efficient dose assessments using these endpoints. However, alternative candidate markers of exposure related to DNA damage have also been investigated in recent years, including protein biomarkers of DSB and gene expression signatures associated with DNA damage signalling. Here the usefulness and applicability of DNA damage-associated biomarkers in environmental exposure assessment is discussed and their adaptability for a “field” setting explored. DNA damage-associated biomarkers of radiation exposure have proven their value in human biodosimetry applications, but all have certain restrictions, especially in the low dose region and in scenarios potentially including other pollutants. Their individual applicability and usefulness very much depends on the exposure scenario in question.