Comparison of in vivo translocation frequencies with invitro G2 radiosensitivity in radiation workers occupationally exposed to external radiation

Abstract

A group of retired workers from the British Nuclear Fuels plc facility atSellafield who had been studied for in vivo translocation frequencies inblood lymphocytes were resampled and analysed for in vitro chromosomalradiosensitivity. Significant variation in response to a dose of 0.5 Gy given at theG2 stage of the cell cycle was observed between individuals(P < 0.001). In a regression analysis that included age, cumulative occupational radiation dose and invitro G2 radiation-induced aberration frequencies as independent variables, only cumulativeoccupational radiation dose had a significant influence on chromosomal translocation frequency(P = 0.0036). G2 in vitro radiosensitivity is assumed to be a marker for genetic polymorphic variation inDNA damage recognition and repair genes. Therefore, since in vivo translocationfrequencies can be considered a surrogate for cancer risk, this lack of association withG2 in vitro radiosensitivity suggests that such genetic variation has no impact on the responseto low dose chronic exposure.