Pre-diagnostic urinary 15-F 2t -isoprostane level and liver cancer risk: Results from the Shanghai Women's and Men's Health Studies.

Oxidative stress has been hypothesized to affect cancer development via various mechanisms, but the evidence from human is limited and inconclusive. 15-F2t -isoprostane (15-F2t -IsoP) is an accurate marker of oxidative stress in humans. Recent studies showed that the evidence of urinary 15-F2t -IsoP level correlating cancer risk is conflicting. We conducted a case-control study nested within two population-based cohort studies. Pre-diagnosis urine samples, collected at cohort enrollment, from 363 incident liver cancer cases and 725 individually matched controls, were used to determine the level of 15-F2t -IsoP by enzyme-linked immunosorbent assay. Conditional logistic regression model was used to estimate the odds ratio to measure the association between the urinary 15-F2t -IsoP level and liver cancer risk. We found that higher pre-diagnostic urinary 15-F2t -IsoP level was associated with an increased liver cancer risk, with an adjusted OR in males (OR4th vs. 1st quartile  = 8.84, 95% CI 2.74-28.60), which was significantly higher than those in females (OR4th vs. 1st quartile  = 1.75, 95% CI 0.70-4.42). HBsAg carriers with higher 15-F2t -IsoP had a significantly increased liver cancer risk (ORfemale  = 59.04, 95% CI 12.26, 284.30; ORmale  = 92.55, 95% CI 34.83, 245.96) compared to non-carriers with lower 15-F2t -IsoP. High urinary 15-F2t -IsoP level was associated with high liver cancer risk, suggesting that 15-F2t -IsoP may be a promising biomarker for liver cancer risk. The result suggests that people with sero-positive HBsAg and higher level of 15-F2t -IsoP might be given a higher priority on future surveillance program of liver cancer.