Occupational radiation exposure and genetic polymorphisms in DNA repair genes

Radiation sensitivity appears to be influenced by genetic polymorphisms in some DNA repair genes and individuals with low DNA repair capacity can be at increased risk of developing cancer. The aim of the present study was to determine the impact of gene polymorphisms on DNA damages in the form of micronuclei (MN) in circulating lymphocytes of interventional cardiologists (ICs), occupationally exposed to ionizing radiation. MN frequency was significantly higher in the ICs than in the controls (27.7 ± 17.2 o/oo vs. 8.0 ± 2.6 o/oo, p < 0.0005). MN values were higher in the ICs with exposure of ≥ 10 years and ≥ 3 mSv in comparison to the related referents. The analysis of different interactions showed significantly higher MN frequencies in ICs exposed to = 10 mSv carrying the variant-type XRCC3 241Met genotype compared to those of wild-type XRCC3 (Thr/Thr) genotype. In the ICs carrying both wild-type alleles for XRCC3 and MSH3 polymorphisms showed a significantly lower MN frequency compared to the exposed individuals with one or two variant alleles for XRCC3 and MSH3 polymorphisms. In conclusion, ICs showed significantly higher MN frequencies than in the control, and this effect was higher in individuals carrying the variant-type XRCC3 241Met genotype. These results not only show the need for improvement of safety and training programs for ICs but also may be helpful in developing amenable screening tests for identifying radiosensitive workers and applying suitable radiation protection job-specific strategies for effective dose reduction. (authors)