E-cadherin gene methylation in lung cancer

E-cadherin, a tumor repressor gene, has been shown to play an important role in maintaining the polarity and structural integrity of epithelial and is closely associated with tumorigenesis, invasion, and metastasis. The current study aimed to investigate the effects of E-cadherin methylation on lung cancer (LC) quantitatively through a meta-analysis. We searched electronic databases to identify eligible studies from their inception through September 30, 2013. Pooled odds ratio (OR) with 95 % confidence interval (CI) was used to assess the relationship between E-cadherin gene methylation and LC risk. A hazard ratio (HR) with 95 % CI was used to assess the impact of E-cadherin gene methylation on overall survival (OS) of LC patients. Seventeen studies comprising 983 LC cases and 669 controls met the inclusion criteria. Summary results revealed that hypermethylation frequencies in LC tissues were significantly higher than those in normal control tissues (OR = 4.11, 95 % CI 2.78-6.07, P < 0.001). Subgroup analysis indicated that higher methylation frequencies were observed in Asian population. Interestingly, we found that hypermethylation of E-cadherin was associated with significantly better survival with HR of 0.47 (95 % CI 0.31-0.71). This meta-analysis revealed that E-cadherin gene promoter methylation was associated with an increased risk of LC, especially in Asian population, and methylated E-cadherin predicted long survival in patients with LC. However, further studies with large numbers of patients will be needed to confirm the findings.