10641 Breast cancer is the most common malignancy among women and its rate of mortality is still high. The increase knowledge of breast cancer biology is heaving great impact on determining the clinical prognosis and response to treatment. Impaired DNA repair may elevate the risk of malignant transformation of breast cells due to the accumulation of spontaneous mutations in target genes and increasing susceptibility to exogenous carcinogens. The present study was designed to evaluate the relationship between DNA damage and expression of some critical genes including TP53, c-ERBB2, ER (Estrogen Receptor) and PR (Progesterone Receptor) in breast cancer. Blood samples were obtained from female patients with diagnosed breast cancer before chemotherapy as well as from healthy individuals, and were processed in 24 hours. To evaluate the role of DNA repair in breast cancer we determined the level of DNA damage and the capacity to remove DNA damage induced by hydrogen peroxide in the peripheral blood lymphocytes. For this purpose the alkaline version of the comet assay, which provides a sensitive tool to investigate DNA damage and repair, was applied. The level of basal DNA damage was higher in breast cancer patients compared to the control group. Considerable inter-individual variations of DNA damage and repair in breast cancer patients were observed both before and after the treatment. The correlation between DNA damage in peripheral blood and expression of p53, c-erbB-2, PR and ER was analyzed. This preliminary study indicates that the DNA damage accumulation, observed in peripheral blood lymphocytes of breast cancer patients in early stages, could be attributed to impaired DNA repair. Our results suggest that DNA damage, as evaluated by the comet assay, seems to be useful molecular biomarker for monitoring ongoing exposures to DNA damaging agents. Such a research on the mutagen sensitivity and efficacy of DNA repair could impact on the development of new diagnostic and screening strategies. Work Supported by FAPERGS and GENOTOX (UFRGS). No significant financial relationships to disclose.
FEATURES OF LYMPHOCYTES IN THE BLOOD IN PATIENTS WITH BASAL-LIKE BREAST CANCER SOUTH-EAST UKRAINE
