Prieto González EA, Ortega Soler M, Fuchs A G, Brito R, Palermo AM, MartÃÂÂÂnez M, Fuentes E.
Nontraditional risk factors in breast cancer have been intensely focused on in recent years. In addition, emphasis has been placed on the gradual variation in preventive paradigms, where identification of susceptible groups of population is of interest. We have evaluated the differences in the repair of oxidative induced DNA damage between pre-menopausal breast tumors patients, and healthy women. Comet assay was chosen as a feasible technique to evaluate DNA repair. Peripheral blood lymphocytes (PBL) were exposed to 100 µM hydrogen peroxide for 5 minutes in ice and then allowed to recover at 37oC for 120 minutes. Results showed that basal DNA damage in patients was not higher than in controls. However, there were significant differences in the amount of DNA repaired at 120 minutes (p <0, 05). The amount of DNA repaired at 120 minutes was 84.5% in the control population versus 63.2% in the premenopausal patient population. Rate of DNA repair was determined in two zones of the curve: from 0 to 30 minutes between the recognition and incision of the lesion when DNA migration reached its maximum and 31 minutes when the comet tail began to shorten until minute 120. The slope of DNA increase in the comet tail during the first ten minutes was significantly lower in patients (mcontrol=10.99 vs mpatients=4, 34), Student t test (p< 0.05), while no differences were found during rejoining. We conclude that comet assay is able to discriminate DNA repair efficiency between breast cancer patients and healthy women.
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