Intrinsic radiosensitivity of healthy donors and cancer patients as determined by the lymphocyte micronucleus assay

Abstract

Purpose

The purpose of the study was to evaluate the usefulness of the cytokines-block micronucleus (MN) assay in assessment of radiosensitivity of lymphocytes in cancer patients.

Material and Method

Lymphocytes from 16 cervical cancer patients, 23 head & neck (H&N) cancer patients, 7 lung cancer patients and 20 healtly donors were analysed using micronucleus assay. Blood sampies from the patients were taken before radiotherapy. Lymphocytes were irradiated in vitro with⁶⁰ Co gamma rays in doses 1, 2, 3 and 4 Gy. The proportion of binucleated cell (BC) and the micronuclei (MN) frequency in BC only were counted.

Results

The propartion of BC in cancer patients ranged from 20 to 55% and was similar in the control group. MN frequency assessed 5 times over 6 months in 4 healthy donors showed that the inter-individual variation was significantly higher than intra-individual. Before (O Gy) and after irradiation (1–4 Gy) no statistical differences in the mean number of MN/BC were observed between healthy donors and cancer patients group, however the highest values were found in lung cancer patients. Nevertheles, statistical cluster analysis allowed to divide each group of donors into radioresistans and radiosensitive subgroups of patients. They showed significantly different (p<0.05) doseresponse relationship. Separate comparison of the mean MN frequency within all examined radioresistant and radiosensitive subgroups, showed statisticaly significant differences only after a dose of 4 Gy. At this dose, the lung cancer patients fram radioresistant subgroups presented significantly lower radioresistance (p<0.05) than the other subgroups, that is control, cervical and H&N cancer patients groups. Within radiosensitive subgroups, lung cancer patients as well as cervical cancer patients show significantly (p<0.05) higher MN frequency in comparison to control and H&N cancer patients.

Conclusion

This work has shown that the MN assay performed on lymphocytes can show differences in the intrinsic radiosensitivity of cancer patients and healthy donors.