SIGNIFICANCE OF SUPEROXIDE-DISMUTASE (SOD) IN HUMAN COLORECTAL-CANCERTISSUE - CORRELATION WITH MALIGNANT INTENSITY

The significance of superoxide dismutase (SOD) activity in colorectal cancer tissue was determined from the aspect of the antioxidant defens e system. SOD activity and thiobarbituric acid reactive substance were measured in the tumor, in tissues adjacent to the tumor, and in regio ns that appeared normal, and the results were analyzed in terms of var ious histopathological factors (stage of disease, depth of invasion, v enous invasion, etc.). DNA ploidy pattern and cell proliferation in ca ncer tissue were also measured, and the results analyzed in relation t o SOD activity. SOD activity in cancer tissue was higher than in the o ther two regions. SOD activity in cancer tissue increased with the pro gression of stage, and changed with the depth of invasion. There was a significant difference in SOD activity between patients with venous i nvasion and those in whom this was absent. Stepwise regression analysi s suggested that venous invasion was the most significant factor influ encing SOD activity. The proliferation index was high in cancer tissue with low SOD activity. The incidence of aneuploidy was high in cancer with high SOD activity, whereas the incidence of diploidy was high in cancer with low SOD activity. These results suggest that elucidation of the antioxidant system in cancer tissue can provide us with a bette r strategy for cancer treatment.