The MPO-463G>A polymorphism and lung cancer risk: a meta-analysis based on 22 case-control studies

Myeloperoxidase (MPO) is an endogenous oxidant enzyme that produces reactive oxygen species (ROS) and may be involved in lung carcinogenesis. The MPO-463G>A polymorphism influences MPO transcription and has been associated with lung cancer susceptibility. However, the association between the MPO-463G>A polymorphism and lung cancer risk remains controversial. To investigate the effect of this polymorphism on lung cancer susceptibility, we performed a meta-analysis based on 22 published case-control studies including 7,520 patients with lung cancer and 8,600 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. Overall, there was no evidence for significant association between MPO-463G>A polymorphism and lung cancer susceptibility (for AA versus GG: OR = 0.91, 95%CI = 0.67-1.24; for GA versus GG: OR = 0.87, 95% CI = 0.78-0.98; for AA/GA versus GG: OR = 0.90, 95% CI = 0.80-1.01; for AA versus OR = 0.96, 95% CI = 0.72-1.28). In the stratified analyses by ethnicity, source of controls and smoking status, we also did not find any significant association between them. In summary, this meta-analysis suggests MPO-463G>A polymorphism may not be a risk factor for developing lung cancer. However, further prospective well-designed population-based studies with larger sample size are expected to validate the results.