Matrix metalloproteinase 2 polymorphisms and expression in lung cancer: a meta-analysis

A number of studies have investigated the role of matrix metalloproteinase 2 (MMP2) polymorphisms and expression in lung cancer, but have yielded inconsistent and inconclusive results. To derive a more precise estimate of the prognostic role of MMP2 expression and the susceptibility role of MMP2 polymorphisms in lung cancer, we reviewed published studies and carried out a meta-analysis. Eligible articles were identified in electronic databases. Case-control studies assessing the associations between MMP2 polymorphisms and lung cancer risk or cohort studies assessing the prognostic role of MMP2 expression in patients with lung cancer were included. Pooled odds ratio (OR) or hazard ratio (HR) with 95 % confidence interval (95 % CI) was used to assess the role of MMP2 polymorphisms and expression in lung cancer, respectively. Seven case-control studies (a total of 3,190 lung cancer cases and 3,013 controls) and 18 cohort studies (2,095 lung cancer patients) were eligible. Meta-analysis of seven case-control studies suggested that individuals with TT genotype of both MMP2 C735T and C1306T polymorphisms had obviously decreased risk of lung cancer compared with those with CC genotype (for MMP2 C735T, fixed effects OR = 0.69, 95 % CI 0.49-0.97, P = 0.032; for MMP2 C1306T, fixed effects OR = 0.54, 95 % CI 0.33-0.86, P = 0.010). Meta-analysis of 18 cohort studies suggested that patients with high MMP-2 expression had poorer overall survival (fixed effects HR = 1.82, 95 % CI 1.56-2.13, P < 0.001). Subgroup by study design, ethnicity and testing methods all further identified the prognostic value of MMP2 expression in lung cancer. In conclusion, MMP2 C735T and C1306T polymorphisms are both associated with lung cancer risk, and patients with high MMP2 expression levels have poorer overall survival compared with those with low MMP2 expression levels.