Abstract
BACKGROUND: DNA promoter methylation of the tumor suppressor genes was one of the key mechanism for gene silence. The aim of this study is to investigate the difference of MGMT gene promoter methylation rate in tumor tissue and autologous controls (serum, normal lung tissue and bronchial lavage fluid) in patients with non-small cell lung cancer (NSCLC). METHODS: The databases of Medline, EMBSE, CNKI and Wanfang were searched for selection of published articles of MGMT gene promoter methylation and non-small cell lung carcinoma risk. The pooled odds ratio (OR) and percentage of MGMT for lung cancer tissue of NSCLC patients compared with normal lung tissue, plasma and the bronchial lavage fluid were pooled. RESULTS: 15 articles of association between MGMT gene promoter methylation and non small cell lung carcinoma risk were included in this meta-analysis. The combined results demonstrated the methylation rate of MGMT in NSCLC cancer tissue was 38% (95%CI: 23%-53%). For normal lung tissue, plasma and the bronchial lavage fluid were 16% (95%CI: 5%-27%), 23% (95%CI: 10%-34%) and 39% (95%CI: 23%-55%) respectively. The OR in cancer tissue was much higher than that in normal lung tissue and plasma odds ratio (OR) 3.98 (95%CI: 2.71-5.84, P<0.05) and OR 1.88 (95%CI: 1.16-3.05, P<0.05), but not in bronchial lavage fluid OR 2.05 (95%CI: 0.88-4.78, P>0.05). CONCLUSIONS: Mehtylation rate in MGMT gene promoter of cancer tissue in NSCLC patients was much higher than that in normal lung tissue and plasma, which showed a close association between NSCLC cancer and MGMT gene promoter methylation.