Cancer stem cell markers predict a poor prognosis in renal cell carcinoma: a meta-analysis

BACKGROUND Relevant markers of CSCs may serve as prognostic biomarkers of RCC. However, their actual prognostic significance remains inconclusive. Thus, a meta-analysis was performed to reevaluate the association of CSCs-relevant markers (CXCR4, CD133, CD44, CD105) expression with RCC prognosis more precisely. METHODS PubMed and Embase were searched to look for eligible studies. The pooled hazard ratios (HR) with 95% confidence intervals (95% CI) were used to reassess the association of CSCs markers expression and RCC prognosis of overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS), and progression-free survival (PFS). RESULTS There were 25 relevant articles, encompassing 2673 RCC patients, eligible for meta-analysis. Overall pooled analysis suggested that high CSCs markers expression predicted poor OS (HR, 2.10, 95% CI: 1.73-2.55) and DFS (HR, 3.77, 95% CI: 2.30-6.19). High CXCR4 expression predicted worse OS (HR, 2.57, 95% CI: 1.95-3.40), CSS (HR,1.97, 95% CI: 1.50-2.59), and DFS (HR, 5.82, 95% CI: 3.01-11.25). CD44 over-expression correlated with a poor OS(HR,1.58, 95% CI: 1.14-2.18), CSS (HR, 2.58, 95% CI: 1.27-5.23), and DFS (HR, 4.49, 95% CI: 2.12-9.53) in RCC patients. CD133 was an independent favorable prognostic factor for CSS (HR, 0.4, 95% CI: 0.29-0.54). CONCLUSIONS The presence of CSCs markers correlates with poor RCC outcome. CSCs may be potentially utilized as prognostic markers to stratify RCC patients, probably representing also a novel potential therapeutic target.