MMP1-1607 1G/2G polymorphism and lung cancer risk: a meta-analysis

Matrix metalloproteinase-1 (MMP-1) plays an important role in the breakdown of extracellular matrix and mediates pathways of apoptosis, angiogenesis, and immunity. It has been demonstrated that MMP-1 overexpression is associated with tumor initiation, invasion, and metastasis. Many studies have investigated the association between MMP1-1607 1G/2G polymorphism and lung cancer risk, but the impact of MMP1-1607 1G/2G polymorphism on lung cancer is unclear owing to the obvious inconsistence among those studies. This study aimed to quantify the strength of the association between MMP1-1607 1G/2G polymorphism and lung cancer risk. We searched the PubMed, Embase, and Wanfang databases for studies on the association between MMP1-1607 1G/2G polymorphism and risk of lung cancer. We estimated summary odds ratio (OR) with its corresponding 95 % confidence interval (95%CI) to assess the association. Overall, MMP1-1607 1G/2G polymorphism was associated with increased risk of lung cancer under four genetic models (OR(2G versus 1G) = 1.21, 95 %CI 1.06-1.37; OR(2G2G versus 1G1G) = 1.36, 95%CI 1.09-1.70; OR(2G2G versus 2G1G+1G1G) = 1.33, 95 %CI 1.10-1.61; and OR(2G2G+2G1G versus 1G1G) = 1.15, 95 %CI 1.04-1.27). Meta-analyses of studies with high quality showed that MMP1-1607 1G/2G polymorphism was still associated with lung cancer risk under those four genetic models. Subgroup analyses by ethnicity and sensitivity analyses further identified the significant association in East Asians. No evidence of publication bias was observed. Meta-analyses of available data show a significant association between MMP1-1607 1G/2G polymorphism and lung cancer risk.