Potential of radiation-induced chromosome aberrations to predict radiosensitivity in human tumour cells

Purpose: To validate whether the number of aberrations could be used as a m easure of the radiosensitivity of human tumour cells. If so, this would pot entially provide a mole rapid method than the colony assay to predict radio curability in human tumour biopsy material. Materials and methods: A panel of 13 human tumour cell lines was investigat ed, covering a wide range of radiosensitivities. Fluorescence in situ hybri dization (FISH) employing whole chromosome probes was used to detect aberra tions. Results: A dose-dependent increase in radiation-induced chromosome aberrati ons was observed in all cell lines. A good correlation (r = 0.90) was found between cell survival and total chromosome aberrations in 12 of the 13 cel l lines (92%), with one exception. A poorer correlation was observed betwee n cell survival and stable- (r = 0.85) and unstable-type aberrations (r = 0 .81). Survival-aberration correlations for individual radiation doses were worse, although statistically significant. The exceptional cell line showed significantly more aberrations for a given level of cell kill than expecte d based on data for the other lines. Conclusion: This study indicates that radiation-induced chromosome aberrati ons can be used as a potential predictor of intrinsic radiosensitivity for the majority of human tumours when more than one dose level is tested. This could aid the design of radiotherapy schedules for each individual patient , or in the decision of whether to use an alternative therapy.