Analysis of oxidative DNA damage in patients with colorectal cancer.

PURPOSE

The aim of this study was to measure the levels of oxidative DNA damage in cells isolated from the colon mucosa in patients with colorectal cancer and to compare normal and neoplastic tissues and make correlations with anatomopathologic variables.

PATIENTS AND METHODS

Thirty-three patients with colorectal adenocarcinoma were studied. The oxidative DNA damage was evaluated by means of the alkaline version of the comet assay.

RESULTS

For all the patients studied, it was found that the cells obtained from the neoplastic tissue presented oxidative DNA damage greater than in the cells from normal tissue. The cells isolated from the neoplastic mucosal tissue of the colon presented significantly greater mean extent of DNA strand breakage than the cells isolated from normal tissue. Additionally, the patients at earlier stages of the Dukes and TNM classifications presented higher levels of oxidative damage than those at more advanced stages.

CONCLUSION

Assessment of the levels of oxidative damage at the different stages of colorectal carcinogenesis is of great interest because it enables evaluation of the effectiveness of antioxidant substances that could be used as preventive measures against the initial oxidative aggressive action on the colonic mucosa.