NQO1 609C>T polymorphism interaction with tobacco smoking and alcohol drinking increases colorectal cancer risk in a Chinese population.

Background: NAD (P)H:quinone oxidoreductase (NQO1) catalyzes the activation of some environmental procarcinogens present in tobacco smoke or the diet. We conducted a hospital-based case-control study to evaluate the potential association between NQO1 609C>T polymorphisms and colorectal cancer risk in a Chinese population.

Methods: The study population comprised 672 histologically confirmed colorectal cancer patients and 672 frequency-matched control subjects without cancer or systemic illness. We used PCR restriction fragment length polymorphism-based methods for genotyping analyses and unconditional logistic regression model for statistical evaluations.

Results: The risk of colorectal cancer increased with the level of smoking and decreased with the consumption of tea, fresh fruits, and vegetables. In addition, we found that the NQO1 609 CT and TT genotypes were associated with an increased risk of colorectal cancer (CT: adjusted OR=2.02, 95% CI=1.55-2.57; TT: adjusted OR=2.51, 95% CI=1.82-3.47), compared with the CC genotype. Moreover, NQO1 609C>T appeared to have a multiplicative joint effect with both tobacco smoking and alcoholic drinking (P for multiplicative interactions were 0.0001 and 0.013, respectively) on colorectal cancer risk.

Conclusion: Our findings suggest that the NQO1 609C>T polymorphism plays an important role in the development of colorectal cancer in the Chinese population, which is strengthened by alcohol drinking or tobacco smoking.