Clinicopathological significance of matrix metalloproteinase-7 protein expression in esophageal cancer: a meta-analysis

BACKGROUND The MMP-7 basement membrane and extracellular matrix may be essential for tumor invasion and metastasis, and the results presented herein showed a relationship between MMP-7 expression and esophageal cancer (EC). However, its clinicopathological value for EC patients remains inconsistent. To clarify their associations, a meta-analysis of the relevant published literature was conducted. MATERIALS AND METHODS Databases including PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, and Google Scholar were electronically searched. Only those studies analyzing MMP-7 expression in EC patients with regard to series of different demographic variables and clinicopathological stages (TNM stage, differentiation and invasion grade, and lymph-node [LN] metastasis) were eligible for inclusion. Summary odds ratios (ORs) were pooled in accordance with the random-effect model. RESULTS Fourteen clinical cohort studies (tumor samples =935) were incorporated into the current meta-analysis. Results revealed that increased MMP-7 expression in EC patients was positively correlated to TNM stage III-IV (OR 3.04, 95% confidence interval [CI] 1.43-6.46; P=0.004). Similar connections were also detected in the differentiation grade, invasion grade, and LN metastasis (all P<0.05). Country-stratified analysis yielded significant association of elevated MMP-7 expression with EC in the People's Republic of China (PRC) under both TNM III-IV versus I-II and differentiation low versus high comparisons (TNM stage, OR 2.01, 95% CI 1.55-2.59, P<0.001; differentiation grade, OR 1.32, 95% CI 1.11-1.57, P=0.002). With regard to invasion grade and LN metastasis, significant association was observed in all the experimental subgroups (all P-values [PRC and Japan] were lower than 0.05). CONCLUSION These data showed an obvious connection between MMP-7 and TNM stages, differentiation grade, invasive grade, and LN metastasis of EC, indicating that overexpression of MMP-7 may be a suitable diagnostic biomarker for variation in EC clinicopathological features.