To determine the association between the urinary excretion of 8-oxodeoxyguanosine (8-oxo-dG) and risk of hepatocellular carcinoma, a case-control study nested within a community based cohort was conducted in Taiwan. Baseline urine samples, collected from a total of 73 HCC cases and 297 matched controls, were used to determine the level of urinary 8-oxo-dG by competitive enzyme-linked immunosorbent assay. Conditional logistic regression analysis was used to calculate odds ratios (OR) and 95% confidence intervals (CI) to assess the effect of urinary 8-oxo-dG on risk of HCC. The geometric mean of urinary 8-oxo-dG was 75.0 ng/μl in HCC cases and 75.5 ng/μl in controls. When compared to subjects in the lowest tertile, there was a decreased trend (ptrend=0.17) in risk of HCC, with increasing tertile of 8-oxodG level (OR=0.78, 95% CI=0.34-1.80; OR=0.55, 95% CI=0.23-1.32, for the 2nd and 3rd tertile relative to the lowest tertile, respectively). In addition, the protective effect of urinary 8-oxo-dG level on HCC risk were only observed among subjects positive for HBsAg. The ORs were 0.26 (95%CI=0.03-2.56), 0.02 (95%CI=0.0-0.78, ptrend<0.05) for subjects with levels of urinary 8-oxo-dG in the 2nd, and 3rd tertile, compared with those in the lowest tertile. Among HBsAg negative subjects, the ORs were 1.59 (95% CI=0.50-5.01), 1.48 (95%CI=0.51-4.27), respectively. Subjects positive for HBsAg and with urinary 8-oxo-dG levels below the mean had a significantly increased HCC risk (OR=27.31, 95%CI=8.07-92.50) compared to subjects negative for HBsAg and with urinary 8-oxo-dG above the mean (ptrend <0.0001). These results demonstrate that elevated urinary excretion of 8-oxo-dG, a possible marker of enhanced repair capacity, is associated with a decreased risk of HCC and that hepatitis B virus infection may modify the role of urinary excretion of 8-oxo-dG in HCC risk.
[Proc Amer Assoc Cancer Res, Volume 47, 2006]