Plasma Selenium Concentration and Glutathione Peroxidase Activity in Breast Cancer Patients Before and After Chemotherapy

Background: The chemotherapeutic agents used for treatment of breast cancer are all shown to increase free oxygen radicals and generation of reactive oxygen species. The aim of this study was to evaluate effect of chemotherapy on plasma selenium (Se) concentration and glutathione peroxidase (GPX) activity in breast cancer patients. Materials and Methods: Seventeen women in stage II and III breast cancer were randomly selected from their population. Plasma Se was measured with Graphite furnace atomic absorption spectroscopy and GPX activity in erythrocyte by using spectrophotometric at baseline (before chemotherapy) and after chemotherapy. normally distributed data was expressed as mean ± standard deviation. Statistical analysis was performed using Paired T-Test. Results: plasma Se concentration before and after chemotherapy was in normal range and no statistically difference was observed (156.23±25 μg/L vs. 145.23±23 μg/L respectively). After chemotherapy, there was a significant (p<0.05) higher erythrocyte GPX activity, as compared to initial activity at baseline. (22.28±4 U/grHb vs. 26.39± 4 U/grHb respectively). Conclusion: This study indicates that sufficient Se could increase GPX activity with have a protective effect against oxidative damages.