Does adenomatous polyposis coli gene promoter 1A methylation increase non-small cell lung cancer risk? A meta-analysis.

Background: The promoter region of the adenomatous polyposis coli (APC) gene is hypermethylated in several types of cancers, including non-small cell lung cancer (NSCLC). The prevalence of methylation in the promoter region of this gene in tumor tissues and autologous controls has not been consistent in previous studies. We evaluated the frequency of APC gene promoter 1A methylation between tumor tissues and autologous controls in NSCLC patients by meta-analysis.

Methods: Open published studies of APC gene promoter 1A methylation between tumor tissues and autologous samples in NSCLC patients were identified using a systematic search. Odds ratios (OR) and 95% confidence intervals (CI) of APC gene promoter 1A methylation in lung cancer tissues versus autologous controls were calculated. Fourteen studies, involving a total of 1345 patients and 2182 samples, were finally included.

Results: The pooled proportion of APC promoter 1A methylation was 0.62 (95% CI 0.52-072) and 0.34 (95% CI 0.21-0.50) in cancer tissues and autologous controls, respectively. The APC gene promoter 1A methylation rate in cancer tissues was much higher than in autologous controls, with a pooled OR of 3.66 (95% CI 2.12-6.33). A strong and significant correlation of APC gene promoter 1A methylation between tumor tissues and autologous controls was detected (correlation coefficient r  = 0.77; P  = 0.0013).

Conclusion: The proportion of APC promoter 1A methylation in lung cancer tissues was higher than in autologous controls, indicating that promoter 1A methylation of the APC gene may play an important role in NSCLC carcinogenesis.