Background: Reactive oxygen species (ROS), including superoxide anion radical (O2(-)), plays an important role in carcinogenesis. The human body has developed different antioxidant systems to defend against free radical attacks. We investigated the changes of the antioxidant status in the blood of patients with breast cancer.
Methods: The O2(-) generation and the levels of malondialdehyde (MDA) were measured as an index of lipid peroxidation along with the examination of the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRx), the levels of reduced glutathione (GSH), oxidized glutathione (GSSG), and vitamins A, C, and E.
Results: The results showed that the levels of O2(-) and MDA, and the activities of antioxidant enzymes in the blood of the patients with breast cancer were significantly higher than the controls. However, the levels of vitamin C, GSH, GSSG and ratio of GSH/GSSG in the blood of the patients with breast cancer were significantly decreased compared to control subjects.
Conclusions: Oxidative stress may be involved in breast cancer. The increased activities of erythrocyte antioxidant enzymes may be a compensatory upregulation in response to the increased oxidative stress.