Prognostic and Clinical Value of CD44 and CD133 in Esophageal Cancer: A Systematic Review and Meta-analysis

Despite the importance of CD44 and CD133 in various cancers, the clinicopathological and prognostic values of these biomarkers in esophageal cancer remain debated. Hence, in this study, we did a meta-analysis to explore the correlation between overexpression of these markers and some clinicopathological features and their influence on the survival of esophageal cancer patients. A search in PubMed and Web of Science (among all articles published up to January 16, 2018) was done using the following keywords: esophageal cancer, CD44, CD133, prominin-1, AC133. Suitable studies, that were selected based on the criteria listed in the Materials and Methods section, were chosen and hazard ratios with 95% confidence intervals were estimated if available. Heterogeneity and sensitivity were also analyzed. Furthermore, publication bias was assessed using funnel plots, Egger, and Begg tests. The study included 1346 patients from 13 related studies. The median rates of marker expressions by immunohistochemistry were 35.7% (30%-76.6%) from 9 studies for CD44 and 31.9% (21%-44.2%) from 5 studies for CD133. The accumulative 5-year overall survival rates of CD44-positive and CD133-positive were 1.59% (1.22-2.06) and 1.27% (0.93-1.73), respectively. Meta-analysis showed that CD44 expression had a significant correlation with 5-year overall survival. CD44 overexpression showed a correlation with some clinicopathological features such as lymph node metastasis, vascular invasion, and recurrence of the disease, while it was not the case for coexpression of CD44 and CD133. In conclusion, CD44 overexpression was associated with a 5-year overall survival rate and thus this biomarker can be a suitable prognostic tool in esophageal cancer.