Background: The findings from studies on the relationship between aldehyde dehydrogenases(ALDH) gene Glu504Lys polymorphism and colorectal cancer(CRC) were inconsistent.

Objectives: The aim of this meta-analysis was to assess ALDH gene Glu504Lys polymorphism and CRC risk.

Methods: All of the relevant studies were identified from PubMed and Embase database. Statistical analyses were conducted with STATA 12.0 software.Odds ratio (OR) with 95% confidence interval (CI) values were applied to evaluate the strength of the association. Nine studies with 2779 cases and 4533 controls were included.

Results: No significant variation in CRC risk was detected in any of the genetic models overall. To explore the sources of heterogeneity,we performed further sub-group analyses by ethnicity and quality assessment of these studies.In the sub-group analysis by race,significant associations between ALDH gene Glu504Lys polymorphism and CRC risk were found in China(Glu/Lys vs Glu/Glu: OR = 0.70, 95%CI = 0.57–0.85; the dominant model: OR =0.69, 95%CI =0.48–0.98) and Japan(Lys/Lys vs Glu/Glu:OR =0.72, 95%CI =0.55–0.95).

Conclusion: This meta-analysis suggests that the ALDH₂ Glu504Lys polymorphism may be associated with susceptibility to CRC. Furthermore, large and well-designed studies are needed to confirm these conclusions.