Abstract: The prominent disadvantage of using GPA mutation frequency as biodosimeter and cancer risk predictor is the significant individual differences. DNA damage and repair ability is one of determinants influencing the individual differences in GPA mutation frequency. With the improvement of current protocols for molecular biology, the measurement of detecting DNA damage and repair ability has been made, such as neutral filter elute, single cell gelelectrophoresis, graded-voltage gel electrophoresis, which make it feasible to modify the individual difference in GPA mutation frequency with DNA damage and repair.