Risk assessment in radiation occupationally exposed people by means of fluorescence in situ hybridization

Full text: Chromosome-type aberrations, such as dicentric and translocation chromes, are biomarkers or exposure to ionizing radiation. Unlike dicentrics, which number reduces by the time, translocations persist in cell division over decades following exposure. There is good mechanistic evidence for the role of translocations in oncogenesis, this provides an insight into the risks associated with low dose exposure. The aim of the present study is to accomplish more precise estimation of radiation induced genotoxic effects in workers from Kozloduy NPP with higher cumulative doses (about 500 mSv) or higher level chromosome aberrations previously registered. FISH and Giemsa staining were used for cytogenetic analysis in human peripheral blood lymphocytes from 30 NPP workers. As control group served 25 subjects from administrative staff. Fluorescence in situ hybridization (FISH) with chromosome - specific DNA probes has been shown to be exceptional way of cytogenetic analysis of radiation induced stable and unstable chromosome aberrations. It was found significantly increased frequency of dicentrics in worker group, compared to controls (p=0.004). The genomic frequency of translocations, investigated by molecular-cytogenetic technique FISH, showed more pronounced increase (p<0.001). Dose response relationship was estimated for both used indicators of radiation exposure. FISH has been proved to be the technique of choice to detect a prolonged low dose occupational radiation exposure