Abstract
BackgroundNAD(P)H:quinone oxidoreductase 1 (NQO1), an obligate two-electron reductase, plays an important role in reducing reactive quinones to less reactive and less toxic hydroquinones. Genetic variations in NQO1 gene that impede its enzyme function may be considered as putative risk factor for cancer. Numerous studies have been performed to investigate the association between NQO1 Pro187Ser polymorphism and bladder cancer risk; nevertheless, the results remain controversial.MethodsWe indentified eligible publications from PubMed, Embase and CBM databases. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to access the strength of the associations. False-positive report probability (FPRP) analysis was also performed for all statistically significant findings.ResultsWe collected a total of 15 studies including 4298 cases and 4275 controls in the final meta-analysis. Overall, the NQO1 187Ser carriers were associated with an increased bladder cancer risk (homozygous: OR = 1.43, 95% CI = 1.08-1.90; recessive: OR = 1.33, 95% CI = 1.03-1.72; dominant: OR = 1.19, 95% CI = 1.04-1.37, and allele comparing: OR = 1.18, 95% CI = 1.06-1.33). Stratification analyses showed a statistically significant association among Asians (homozygous: OR = 1.82, 95% CI = 1.39-2.38; recessive: OR = 1.52, 95% CI = 1.20-1.93, dominant: OR = 1.40, 95% CI = 1.05-1.88, and allele comparing: OR = 1.35, 95% CI = 1.15-1.58), never smokers (homozygous: OR = 2.30, 95% CI = 1.14-4.65; heterozygous: OR = 2.26, 95% CI = 1.43-3.56; dominant model: OR = 1.59, 95% CI = 1.14-2.21, and allele comparing: OR = 1.72, 95% CI = 1.27-2.33), hospital-based studies (homozygous: OR = 1.46, 95% CI = 1.09-1.94; recessive: OR = 1.32, 95% CI = 1.02-1.69; dominant: OR = 1.28, 95% CI = 1.05-1.56, and allele comparing: OR = 1.24, 95% CI = 1.07-1.43), studies with genotyping performed by PCR-RFLP under all genetic models, and studies with minor allele frequency >0.30 (homozygous: OR = 1.69, 95% CI = 1.25-2.27; recessive: OR = 1.46, 95% CI = 1.10-1.95, and allele comparing: OR = 1.25, 95% CI = 1.04-1.51), respectively.ConclusionsDespite some limitations, our meta-analysis provides sufficient evidence that NQO1 Pro187Ser polymorphism may contribute to bladder cancer risk. These findings need further validation in well-designed prospective studies with larger sample size and different ethnicities, especially for Asians.
Highlights
Cancer is a major public health burden worldwide
The NAD(P)H:quinone oxidoreductase 1 (NQO1) 187Ser carriers were associated with an increased bladder cancer risk
NQO1 Pro187Ser Polymorphism and Bladder Cancer Risk allele comparing: odds ratios (ORs)=1.72, 95% confidence intervals (CIs)=1.27-2.33), hospital-based studies, studies with genotyping performed by PCR-RFLP under all genetic models, and studies with minor allele frequency >0.30, respectively
Summary
Cancer is a major public health burden worldwide. Approximately 12.7 million new cancer cases and 7.6 million cancer deaths were reported based on GLOBOCAN 2008 [1]. Bladder cancer is the seventh most frequently diagnosed cancer among men, with about 386300 new cancer cases and 150200 cancer deaths in 2008 [1]. It is clear that cancer is a multistep process involving complex interactions between environmental and genetic factors [2,3]. Despite the environmental factors play important roles in the development of cancer, host genetic factors are closely related to the pathophysiology of many human cancers including bladder cancer [5]. Genetic variations in NQO1 gene that impede its enzyme function may be considered as putative risk factor for cancer. Numerous studies have been performed to investigate the association between NQO1 Pro187Ser polymorphism and bladder cancer risk; the results remain controversial
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