Prognostic Value of Cancer Stem Cell Marker CD133 Expression in Gastric Cancer: A Systematic Review

OBJECTIVE To investigate the correlation between CD133-positive gastric cancer and clinicopathological features and its impact on survival. METHODS A search in the Medline and Chinese CNKI (up to 1 Dec 2011) was performed using the following keywords gastric cancer, CD133, AC133, prominin-1 etc. Electronic searches were supplemented by hand searching reference lists, abstracts and proceedings from meetings. Outcomes included overall survival and various clinicopathological features. RESULTS A total of 773 gastric cancer patients from 7 studies were included. The median rate of CD133 expression by immunohistochemistry (IHC) was 44.8% (15.2%-57.4%) from 5 studies, and that by reverse transcription polymerase chain reaction (RT-PCR) was 91.3% (66.7%-100%) from 4 studies. The accumulative 5-year overall survival rates of CD133-positive and CD133-negative patients were 21.4% and 55.7%, respectively. Meta-analysis showed that CD133-positive patients had a significant worse 5-year overall survival compared to the negative ones (OR = 0.20, 95% CI 0.14-0.29, P<0.00001). With respect to clinicopathological features, CD133 overexpression by IHC method was closely correlated with tumor size, N stage, lymphatic/vascular infiltration, as well as TNM stage. CONCLUSION CD133-positive gastric cancer patients had worse prognosis, and was associated with common clinicopathological poor prognostic factors.