Disturbances in the mechanisms of antioxidant defense (a decrease in the concentration of reduced glutathione, an increase in superoxide dismutase activity, a decrease in the activity of glutathione peroxidase) and the intensity of oxidative damage to cells (an increase in the content of MDA, protein carbonyl groups and 8-OHdG) were previously shown in the blood serum of patients with BRCA1-dependent breast cancer [46,47]. The gene discussed is BRCA1; the disease is breast carcinoma.