Increased Plasma Levels of 8-Hydroxydeoxyguanosine Are Associated with Development of Colorectal Tumors

Increased oxidative stress is generally thought to be associated with tumorigenesis. In this cross-sectional study, we evaluated plasma 8-hydroxydeoxyguanosine (8-OHdG) levels in patients with colorectal adenoma and cancer, as a surrogate marker of oxidative damage to deoxyribonucleic acid (DNA). We collected blood samples from 58 patients with adenoma, 32 with early cancer, 25 with advanced cancer, and 36 without polyps or cancer (as controls), and measured plasma levels of 8-OHdG by enzyme-linked immunosorbent assay. Univariate analysis by logistic regression showed that an increased level of 8-OHdG was a significant risk for adenoma [odds ratio (OR) 1.393, 95% confidence interval (CI) 1.008-1.926, p = 0.045]. In patients with early cancer, univariate analysis revealed significant differences for age, body mass index (BMI), systolic blood pressure, and 8-OHdG level. Subsequent multivariate analysis revealed that 8-OHdG [OR 1.627, 95% CI 1.079-2.453, p = 0.020] and BMI [OR 1.283, 95% CI 1.038-1.585, p = 0.021] were significant risk factors for early cancer. However, 8-OHdG was not a significant risk factor for advanced cancer. Our results suggest that an increased plasma level of 8-OHdG is associated with development of colorectal adenoma and cancer.