Abstract: OBJECTIVE: To explore the association between COX-2 expression in human esophageal cancer and its clinicopathologic characteristics of esophageal cancer. METHODS：Published studies were searched in the CBMdisc(1978-2011)，CNKI(1979-2010)，VIP(1989-2010) database，CMA Digital Periodicals(1998-2010)，other relevant journals were manually searched to identify all the related case-control studies in mainland China. The quality of the included studies was assessed. Cochrane Collaboration’s Software Revman 5.0.2 was utilized to test the heterogeneity， the overall effect and the publication bias of the combined studies as well. RESULTS：Seven studies were included. For the positive rate of COX-2 expression，significant difference was tested between esophageal cancer and normal esophageal tissues[OR=31.44，95%CI(10.47，94.38)]. In addition，cell differentiation G1+G2 vs. cell differentiation G3 revealed significant difference[OR=3.60，95%CI(1.63，7.99)]. However，there was not any significant difference shown in terms of gender，age，depth of invasion，lymph node metastasis，of which the overall effect were 1.56 (0.61，3.98)，0.59(0.27，1.30)、1.21(0.49，2.98)，1.47 (0.38，5.64)，respectively. CONCLUSION：According to the currently available national evidence，higher COX-2 expression may be associated with esophageal cancer and cell differentiation.

Key words: esophageal cancer, cyclooxygenase-2, Meta-analysis