Correlation of radiation-induced micronucleus frequency with clonogenic survival in cells of one diploid and two tetraploid murine tumor cell lines of the same origin.

Whether the micronucleus assay can be used as a predictive tool to estimate the intrinsic cellular radiosensitivity depends on whether the results correlate with clonogenic survival. In the present study we investigated the influence of the ploidy on the correlation of the two assays by comparing cells of one diploid and two tetraploid murine tumor cell lines of different radiosensitivities. A definite correlation between survival and micronucleus frequency is evident for all three cell lines investigated. The rank order of the frequency of micronucleus expression correlates with that of clonogenic survival in the cell lines studied. No influence of DNA content on the radiosensitivity and the relationship between the micronucleus frequency and clonogenic survival could be observed. Thus our results are promising for the clinical application of the micronucleus assay as a predictive measure of radiosensitivity. However, it is necessary to consider such factors such as cell proliferation kinetics which may influence the correlation between micronucleus frequency and clonogenic survival.