Imbalance of Antioxidant Processes in Red Blood Cells—A Universal Factor of Pathogenesis of Cancer-Associated Anemia

The features of free radical oxidation in red blood cells coupled with the development of anemia in non-small cell lung cancer and breast cancer have been studied. In cancer, the imbalance of antioxidant enzymes activities was detected in red blood cells. For example, a 2-fold increase in the activity of superoxide dismutase (SOD) on the average (p < 0.001) was accompanied by a 1.5-fold decrease in the activity of glutathione peroxidase (GPO) (p < 0.005). According to the Spearman’s rank correlation, the decrease in GPO activity is coupled with the development of anemia, correlates with the decrease in hemoglobin (Hb) and hematocrit (HTC). The values of Spearman’s rank correlation coefficient are ρ = 0.76 for GPO and Hb; ρ = 0.74 for GPO and HTC. Anemia develops under the conditions of intensification of pro-oxidant processes and impaired gas transport function of red blood cells, as is demonstrated by positive correlation between the levels of malonic dialdehyde and 2,3-diphosphoglycerate (ρ = 0.54), which increased during its development (ρ = 0.74). The revealed impairments are universal and have been observed both in non-small cell lung cancer and in breast cancer.