The ratio of MDA/SOD and MDA/CAT clearly decreased in the patients in group D compared with the patients in group C, and were significantly higher in comparison with group A. This indicated that in patients with stages III–IV gastric cancer, the dynamics of an increase in SOD and CAT in the plasma was higher in comparison with the change in the concentration of MDA than in patients with stages I–II gastric cancer (Figure 3). This evidence concerns the gene CAT and gastric cancer.