Prognostic Value and Clinicopathological Differences of Bmi1 in Gastric Cancer: A Meta-analysis

B cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) was identified as a biomarker of cancer stem cells, and over-expression of Bmi1 might enhance tumor aggressive clinical behavior in gastric cancer (GC). Our aim of this meta-analysis is to investigate the prognostic role and clinicopathological differences of Bmi1 in GC patients. A total of 6 studies up to September 2014 were included in our study. Our results showed that there were no relationships between Bmi1 expression and the gender (pooled OR=0.87, 95%CI=0.66-1.14, P=0.319, fixed effect), age (pooled OR=1.22, 95%CI=0.95-1.59, P=0.126, fixed effect) and differentiation (pooled OR=1.15, 95%CI=0.71-1.86, P=0.582, random effect) in GC patients. But high Bmi1 expression was significantly correlated with the clinical stage (pooled OR=3.04, 95%CI=1.31-7.07, P=0.010, random effect), tumor size (pooled OR=2.01, 95%CI=1.14-3.55, P=0.016, random effect), T classification (pooled OR=2.79, 95%CI=1.94-4.03, P<0.001, fixed effect), lymph node metastasis (pooled OR=2.24, 95%CI=1.47-3.39, P<0.001, random effect) and distant metastasis (pooled OR=5.05, 95%CI=1.29-19.70, P=0.020, random effect), and led to a poor overall survival (OS) in GC patients (RR=3.38, 95%CI=2.43-4.69, P<0.001, fixed effect). These findings suggested that Bmi1 might serve as a novel and effective prognostic biomarker in GC, and could be a promising emerging molecular target in GC therapy.