Clinicopathological characteristics and prognostic value of the cancer stem cell marker ALDH1 in ovarian cancer: a meta-analysis

BACKGROUND: The clinicopathological and prognostic values of the cancer stem cell marker aldehyde dehydrogenase 1 (ALDH1) in ovarian cancer (OC) remain unknown. The aim of our meta-analysis was to evaluate ALDH1’s association with clinicopathological characteristics and its prognostic significance in patients with OC. MATERIALS AND METHODS: PubMed, Embase, and China Biology Medicine were systematically searched for eligible studies (up to October 2017). Pooled odds ratios (ORs) or hazard ratios (HRs) with 95% CIs were used to evaluate the association of ALDH1 expression with clinicopathological features and survival outcomes. RESULTS: A total of 17 papers (18 studies) that included 2,531 patients with OC were analyzed. The results showed a significant association between increasing ALDH1 expression and International Federation of Gynecology and Obstetrics stage (OR 2.02, 95% CI 1.16–3.52), lymph node metastasis (OR 1.91, 95% CI 1.01–3.61), and distant metastasis (OR 5.43, 95% CI 1.44–20.42) in OC. However, no significant correlation was found between increasing ALDH1 expression and age (OR 0.90, 95% CI 0.25–3.28), tumor size (OR 1.13, 95% CI 0.75–1.71), tumor location (OR 0.69, 95% CI 0.22–2.13), ascite status (OR 0.74, 95% CI 0.49–1.11), resistance status (OR 0.70, 95% CI 0.14–3.51), or clinicopathological type (OR 1.14, 95% CI 0.69–1.86). Moreover, a high ALDH1 expression was significantly associated with overall survival (HR 1.56, 95% CI 1.21–2.02) but not with disease-free survival (HR 1.38, 95% CI 0.99–1.93). CONCLUSION: The meta-analysis indicates that increasing ALDH1 predicts poor prognosis and clinicopathological characteristics in OC. Future studies are needed to explore tailored treatments that directly target ALDH1 for the improvement of survival in OC.