Promoter methylation of the RASSF1A gene may contribute to colorectal cancer susceptibility: a meta-analysis of cohort studies.

This meta-analysis of published cohort studies was conducted to evaluate whether promoter methylation of the RASSF1A gene contributes to colorectal cancer (CRC) susceptibility. A range of electronic databases were searched without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. Crude risk differences (RD) with their 95% confidence intervals (95%CI) were calculated. In this meta-analysis, 11 clinical cohort studies with a total of 630 CRC patients were included. The pooled results revealed that the frequency of RASSF1A gene methylation in cancer tissues was significantly higher than that in benign, adjacent, and normal tissues (cancer tissues vs. benign tissues: RD = 0.25, 95%CI = 0.13-0.38, P < 0.001; cancer tissues vs. adjacent tissues: RD = 0.32, 95%CI: 0.20-0.45, P < 0.001; cancer tissues vs. normal tissues: RD = 0.38, 95%CI: 0.26-0.50, P < 0.001; respectively). Subgroup analysis by ethnicity demonstrated that RASSF1A promoter methylation also exhibited a higher frequency in cancer tissues among both Asians and Caucasians (all P < 0.05). Our meta-analysis has shown positive correlations between RASSF1A promoter methylation and CRC susceptibility. Thus, detection of RASSF1A promoter methylation may be utilized as a valuable diagnostic marker for CRC.