NAD(P)H: quinone oxidoreductase 1 (NQO1) C609T polymorphism and lung cancer risk: a meta-analysis.

No clear consensus has been reached on the NAD(P)H: quinone oxidoreductase 1 (NQO1) gene C609T polymorphism and lung cancer risk. We performed a meta-analysis to summarize the possible association. We conducted a computer retrieval of PubMed and Embase databases prior to May 2013. References of retrieved articles were also screened. The fixed-effects model and the random-effects model were applied for dichotomous outcomes to combine the results of the individual studies. According to the inclusion criteria, 25 articles (32 studies) were finally included. There was no statistical association between C609T polymorphism and lung cancer risk in overall, East Asians, African Americans, or Hispanics. In Caucasians, a significant association was found in allele comparison model (T vs. C) (P = 0.04, OR = 1.09, 95% CI 1.00-1.19, P(heterogeneity) = 0.24, fixed-effects model). In the subgroup of squamous cell carcinoma, a borderline significance could be found in the dominant genetic model (TT + CT vs. CC) (P = 0.05, OR = 1.20, 95% CI 1.00-1.43, P(heterogeneity) = 0.65, fixed-effects model). Significant association could also be found in allele comparison (T vs. C) (P = 0.03, OR = 1.21, 95% CI 1.01-1.44, P(heterogeneity) = 0.68, fixed-effects model). In the subgroup of small cell lung cancer risk, significant association were found in allele comparison (T vs. C) (P = 0.03, OR = 1.68, 95%CI 1.05-2.68, P(heterogeneity) = 0.10, random-effects model) and in the homozygote comparison (TT vs. CC) (P = 0.02, OR = 2.79, 95% CI 1.14-6.85, P heterogeneity = 0.72, fixed-effects model). No association was observed in adenocarcinoma subgroup. Our study suggested that NQO1 C609T polymorphism might associate with lung cancer risk in Caucasians. This polymorphism might also associate with squamous cell carcinoma and small cell lung cancer risk.