Clinicopathological and prognostic role of MMP-9 in esophageal squamous cell carcinoma: a meta-analysis

Objective:Many studies reported that matrix metalloproteinase-9(MMP-9)participated in the development of esophageal squamous cell carcinoma(ESCC)and resulted in poor prognosis,however,they all included few patients and had inconsistent results.So we conducted a meta-analysis to explore the correlation between overexpression of MMP-9 and the clinicopathological characteristics and overall survival(OS)of ESCC.Methods:PubMed,EMBASE,Web of Science,Chinese Biomedical Literature Database,Google Scholar and other databases were searched for relevant studies.The Newcastle-Ottawa quality assessment scale was used to assess the methodological quality of included study and RevMan 5.2 software was used to conduct meta-analysis.Results:A total of 35 studies were included,and the results of meta-analysis showed that overexpression of MMP-9 was associated with grade of differentiation[well/moderate vs.poor:odds ratio(OR):0.39,95%confidence interval(CI):0.29-0.52;P<0.00001],lymph node metastasis(negative vs.positive:OR:0.24,95%CI:0.16-0.34;P<0.00001),TNM stage(T1/T2 vs.T3/T4:OR:0.28,95%CI:0.14-0.54;P=0.0002),the depth of invasion(T1/T2 vs.T3/T4:OR:0.29,95%CI:0.17-0.49;P<0.00001),and vascular invasion of ESCC(negative vs.positive:OR:0.35,95%CI:0.21-0.58;P<0.0001),and also associated with poor overall survival of ESCC(HR:2.17,95%CI:1.32-3.57;P=0.002).Subgroup analysis showed that more than 10%of carcinoma cell staining was associated with significant increase of mortality risk(HR:2.44,95%CI:1.16-5.15;P=0.02),and sensitive analysis suggested that MMP-9 was an independent prognostic factor in ESCC(HR:1.49,95%CI:1.16-1.91;P=0.002).Conclusions:On the basis of limited evidence,overexpression of MMP-9 may be a potential independent prognosis factor of ESCC patients in Asia,and high-quality studies assessing the prognostic significance of MMP-9 for ESCC patients are still needed.