Prognostic significance of cyclooxygenase-2 protein in pancreatic cancer: a meta-analysis

We conducted a meta-analysis of relevant cohort studies to investigate the relationships between cyclooxygenase-2 (COX-2) protein and the prognosis of pancreatic cancer. The following electronic databases were searched without language restrictions: MEDLINE (1966 similar to 2013), the Library Database (Issue 12, 2013), EMBASE (1980 similar to 2013), CINAHL (1982 similar to 2013), Web of Science (1945 similar to 2013), and the Chinese Biomedical Database (CBM) (1982 similar to 2013). Meta-analysis was performed using the STATA statistical software. Six cohort studies with a total of 712 pancreatic cancer patients were involved in this meta-analysis. Our findings showed that COX-2-positive patients were significantly associated with a shorter overall survival (OS) than COX-2-negative patients (hazard ratio (HR)=1.48, 95 % confidence interval (95% CI)= 1.12 similar to 1.85, P<0.001). A subgroup analysis by ethnicity also revealed that pancreatic cancer patients with an abnormal COX-2 expression exhibited a worse OS than COX-2-negative patients among both Asians and Caucasians (Asians: HR=1.40, 95% CI=-0.09 similar to 2.89, P=0.066; Caucasians: HR=1.49, 95% CI=1.11 similar to 1.87, P<0.001, respectively). Our findings provide empirical evidence that abnormal COX-2 expression may be strongly correlated with poor prognosis for patients with pancreatic cancer. Thus, COX-2 protein may be a useful biomarker for pancreatic cancer.