The comparison of erythrocyte glutathione peroxidase activity, erythrocyte malondialdehyde and plasma selenium levels in breast cancer patients of different clinical stage

Objectives : To investigate the roles of oxidative stress, selenium and antioxidant enzyme in breast cancer patients of different clinical stage. Design and Method : Erythrocyte malondialdehyde (MDA), serum selenium levels and erythrocyte glutathione peroxidase (GPx) activities were measured at study groups and healty controls. Atomic absorption spectrophotometry and colorimetric method were used to obtain selenium and MDA levels, respectively GPx activities were assesed with kinetic method described by Paglia and Valentine. Results : In the present study the erythrocyte (GPx) activities of all study groups (group A, group B, group C) were significantly higher than healty control (p<0,001). Significantly increased lipid peroxidation, measured as erythrocyte MDA, was demonstrated in breast cancer patients compared to the control (p<0,001) with contrast to serum selenium levels which were significantly lower in patients' group than the control (p<0,001). Conclusion : In the present study the presence of an association among oxidative stress, selenium and antioxidant system was observed in patients with breast cancer.