Role of CDH1 promoter methylation in colorectal carcinogenesis: a meta-analysis.

This meta-analysis was performed to evaluate the role of CDH1 promoter methylation in colorectal carcinogenesis. The PubMed, CISCOM, CINAHL, Web of Science, Google Scholar, EBSCO, Cochrane Library, and CBM databases were searched for relevant articles published before November 1st, 2013 without any language restrictions. Meta-analysis was conducted using the STATA 12.0 software. Crude odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated. Nine clinical cohort studies met all our inclusion criteria and were included in this meta-analysis. A total of 883 colorectal cancer (CRC) patients were assessed. Our meta-analysis results revealed that the frequencies of CDH1 promoter methylation in CRC tissues were higher than those in control tissues (OR=2.61, 95% CI=1.24-5.50, p=0.012). A subgroup analysis by ethnicity showed that CDH1 promoter methylation was closely linked to the pathogenesis of CRC among Asians and Africans (Asians: OR=2.90, 95% CI=1.26-6.67, p=0.012; Africans: OR=3.81, 95% CI=1.56-9.34, p=0.003; respectively), but not among Caucasians (OR=1.68, 95% CI=0.24-11.72, p=0.598). A further subgroup analysis by type of control tissues suggested that CRC tissues also exhibited higher frequencies of CDH1 promoter methylation than those of normal and adjacent tissues (normal: OR=1.57, 95% CI=1.12-2.21, p=0.009; adjacent: OR=5.07, 95% CI=2.91-8.82, p<0.001; respectively). However, we found no evidence for any significant difference in the frequencies of CDH1 promoter methylation between CRC tissues and adenomas tissues (OR=1.18, 95% CI=0.74-1.90, p=0.485). Our findings provide empirical evidence that CDH1 promoter methylation may play an important role in colorectal carcinogenesis. Thus, CDH1 promoter methylation may be a useful biomarker for the early diagnosis of CRC.