CD133 expression may be useful as a prognostic indicator in colorectal cancer, a tool for optimizing therapy and supportive evidence for the cancer stem cell hypothesis: a meta-analysis.

We performed a meta-analysis of CD133-related clinical data to investigate the role of cancer stem cells (CSCs) in the clinical outcomes of colorectal cancer (CRC) patients, analyzing the effectiveness of various therapeutic strategies and examining the validity of the CSC hypothesis. For 28 studies (4546 patients), the relative risk (RR) to survival outcomes associated with CD133+ CRCs were calculated using STATA 12.0 software. Pooled results showed that CD133High patients had poor 5-year overall survival (RR 0.713, 95% CI 0·616-0·826) and 5-year disease free survival (RR 0·707, 95% CI 0·602-0·831). Both associations were consistently observed across different races, research techniques and therapeutic strategies. In a subgroup receiving adjuvant therapy, CD133Low patients achieved significantly better survival than CD133High patients. The findings suggest that CD133 could serve as a predictive marker of poor prognosis and treatment failure in CRC. CD133Low patients could benefit from adjuvant treatments, while CD133High patients should be given novel treatments besides adjuvant therapy. Our results also provide evidence in support of the CSC hypothesis.