Elevated matrix metalloproteinase-7 expression promotes metastasis in human lung carcinoma

Background Matrix metalloproteinase 7 (MMP-7) promotes tumor invasion and metastasis in several cancers. However, its role in lung cancer progression is understudied. In this study, we investigated the correlation between MMP-7 expression and lung cancer pathology. Methods We searched the databases PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, China BioMedicine (CBM) and China National Knowledge Infrastructure (CNKI) for scientific literature relevant to MMP-7 and lung cancer. Carefully selected studies were pooled and ORs with 95% CI were calculated. Subgroup analyses and publication bias were analyzed to understand the retrieved data in greater detail. Version 12.0 STATA software was used for statistical analysis. Results We retrieved a total of 121 studies through database searches. Finally, 14 cohort studies satisfied our inclusion/exclusion criteria, and these 14 studies, published between 2004 and 2012, were selected for meta-analysis to understand the influence of MMP-7 expression in lung cancer progression. Our results showed consistent differences in MMP-7 expression when comparisons were made between TNM I-II versus III-IV (OR = 1.82, 95% CI: 1.19 to 2.78, P = 0.006); histologic grade 1 to 2 versus 3 to 4 (OR = 1.67, 95% CI: 1.14 to 2.42, P = 0.008); and lymph node-negative versus lymph node-positive samples (OR = 2.81, 95% CI: 1.73 to 4.58, P