Relationships between abnormal MMP2 expression and prognosis in gastric cancer: a meta-analysis of cohort studies

We carried out this current meta-analysis of relevant cohort studies in an attempt to investigate the relationships between abnormal matrix metalloproteinases-2 (MMP2) expression and gastric cancer (GC) prognosis. A range of electronic databases were searched for relevant articles without any language restrictions: Web of Science (1945-2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966-2013), EMBASE (1980-2013), CINAHL (1982-2013), and the Chinese Biomedical Database (CBM) (1982-2013). Meta-analysis was conducted using the STATA 12.0 software. Crude hazard ratios (HRs), with 95% confidence intervals (95% CIs), were calculated. Ten clinical cohort studies with a total of 1669 GC patients were included in this meta-analysis. The results of our meta-analysis suggested that MMP2-positive patients display a shorter overall survival (OS) than MMP2-negative patients (HR=1.31, 95% CI=0.98-1.63, p<0.001). Subgroup analysis based on ethnicity revealed that abnormal MMP2 expression was associated with significantly worse OS in patients with GC among both Caucasian and Asian populations (all p<0.05). Our meta-analysis indicated that abnormal MMP2 expression may be strongly correlated with poor prognosis in patients with GC. Thus, MMP2 expression may serve as an independent prognostic factor for GC.