The prognostic value and clinicopathological significance of CD44 expression in ovarian cancer: a meta-analysis

The prognostic value and clinicopathological significance of CD44 in ovarian cancer (OC) remain unclear. This meta-analysis, therefore, aims to evaluate the correlation between CD44 expression and OC. Studies published until March 2016 were searched in PubMed, EMBASE, and ISI Web of Knowledge databases. The odds ratio (OR) and the hazard ratio (HR) with 95 % confidence interval (CI) were used to assess the effects. Twenty-four studies that include 2267 OC patients were identified for the final analysis. Sixteen studies investigated the expression difference of CD44 standard (CD44s) in 1848 patients. Results showed that high CD44s expression is associated with chemoresistance (OR 5.94, 95 % CI 1.91-18.47) and short disease-free survival (DFS) time (HR 2.57, 95 % CI 1.34-4.91). In addition, CD44s expression is not associated with tumor differentiation grade, residual mass, lymphoid nodal metastasis, and overall survival (OS). Ten studies investigated the expression difference of CD44v6 in 724 patients. Results showed that the CD44v6 expression is not correlated with FIGO stage, tumor differentiation grade, lymphoid nodal metastasis, and OS. High CD44s expression possibly indicates poor prognosis in OC patients given that high CD44s expression initiates chemotherapy resistance, although this expression pattern is not an independent predictive factor for OS. Meanwhile, high CD44s expression may be related to poor DFS of OC, but this relationship must be further confirmed. In addition, the result in which CD44v6 is not associated with OS of OC patients should be interpreted with caution.