EVALUATION OF MARKERS OF OXIDATIVE DNA DAMAGE IN FEMALES WITH BREAST TUMORS

Background: DNA damage reflects a balance between oxidative stress and DNA repair ability which associates with breast cancer risk.
Objective: Assessment of the oxidative DNA damage in women with breast tumors using comet tail length (CTL) and comet tail moment (CTM) to measure the extent of single strand DNA breaks in addition to 8-hydroxy deoxy guanosine (8-OHdG) levels and numbers of DNA lesions.
Methods: Blood leukocytes and post operative tumor specimens were taken from 40 females with newly diagnosed breast tumors (age 24-75 years) and leukocytes of 40 healthy controls (age range 24-50 years). The cells were subjected to single cell agarose gel electrophoresis and the severity of DNA damage was quantitated by computer image analysis. The level of the 8-OHdG was measured by ELISA and numbers of DNA lesions was estimated by special formula.
Results: There were highly significant differences(P<0.001) in the mean levels of leukocyte CTL, CTM, serum 8-OHdG and DNA lesion in benign and malignant breast tumor as compared to the control groups with augmented elevations in these analytes in malignant breast tumor tissues as compared to the benign ones. A Significant increase (p<0.001) in the mean tissue 8-OHdG values was reported in the invasive malignant carcinoma as compared with noninvasive subgroup. The leukocyte means of CTL, CTM, 8-OHdG of malignant breast tumor patients with an age ≤ 48 years and BMI >24 were significantly higher than their counterparts (p<0.05, P<0.001, respectively). There were strong positive correlation between both leukocytes ( r=0.71, r=0.83; P<0.001) and tissue (r=0.69, r=0.83; P<0.001) CTL, CTM with the concentration of serum 8-OHdG in total breast tumors.
Conclusion: The 8-OHdG and comet assays are useful, sensitive markers for monitoring the severity of DNA modification and damage in breast tumor and could be used to identify persons with increased cancer susceptibility.
Keywords: Comet test, 8-hydroxy deoxy guanosine, oxidative DNA damage, Breast tumors.