CORRELATION BETWEEN ANTIOXIDANT ENZYME-ACTIVITIES AND THE CHROMOSOME-DAMAGE INDUCED BY RADIOTHERAPY AND CHEMOTHERAPY IN BREAST-CANCER PATIENTS

Background - There is evidence indicating that SOD activity may influe nce the chromosomal sensitivity of lymphocytes to radiation and radiom imetic agents. Methods - The physiological activities of antioxidant e nzymes (AOE) catalase (CAT), peroxidases (POD) and superoxide dismutas e (SOD) in whole blood and the yield of radio- and/or chemotherapy-ind uced chromosome damage were studied in 8 breast cancer patients. Enzym atic dosages were performed before therapy. Results - Blood AOE activi ties were higher in the cancer patient group than in the normal contro l group. In patients treated with radiotherapy we found a negative cor relation between SOD levels and chromosomal radiosensitivity. Patients treated with radiation plus chemostatic compounds showed lower freque ncies of chromosome aberrations than patients treated with radiation o nly. This effect was probably due to the mortality of lymphocytes with high levels of chromosomal aberrations. Correlation between AOE level s in blood and in normal and cancer mammary tissues showed a significa nt negative correlation between SOD activity in blood and cancer cells and a significant positive correlation between POD in blood and cance r tissues. Conclusions - Our results suggest that SOD activity in whol e blood may be useful to estimate the radiation dose to employ in the therapy of breast cancer.