Prognostic significance of cancer stem cell marker CD133 expression in breast cancer

CD133 has been commonly used as a cancer stem cell (CSC) marker in breast cancer. However, the correlation between CD133 expression, and clinicopathological characteristics and prognosis in breast cancer, remains inconsistent. This study was designed to explore the relationship between CD133 and clinicopathological characteristics, as well as overall survival (OS), through meta-analysis. An electronic search was conducted utilizing the databases of PubMed, Embase, and the Web of Science, up to October 21, 2016. Pooled odds ratios (ORs), and hazard ratios (HRs) with 95% confidence intervals (CIs), were calculated. Publication bias was estimated using Begg's test and Egger's test. A total of 11 studies involving 1447 patients were included in this meta-analysis. The data showed that CD133 expression was correlated with a G3 tumor grade (OR=1.82, 95% CI=1.4-2.36, P<0.001), the presence of lymph node metastasis (OR=2.21, 95% CI=1.75-2.79, P<0.001), negative PR status (OR=0.62, 95% CI=0.47-0.81, P=0.001), negative ER status (OR=0.4, 95% CI=0.19-0.86, P=0.018), advanced TNM stage (OR=2.74, 95% CI=2.05-3.66, P<0.001) and positive HER2 status (OR=2.00, 95% CI=1.04-3.85, P=0.039). Furthermore, CD133 expression was correlated with poor OS (HR=2.04, 95% CI=1.32-3.14, P<0.001). There was no significant publication bias in this meta-analysis. The present meta-analysis demonstrated that CD133 expression was correlated with several clinicopathological characteristics and a poor prognosis. CD133 can be considered as an effective tool for pathological diagnosis and prognostic prediction in breast cancer.