Zhao W, et al. - The association of aldehyde dehydrogenase 1 (ALDH1, the cancer stem cell marker) expression with clinicopathological features and survival outcomes in patients with ovarian cancer (OC) was determined by analyzing a total of 17 papers (18 studies) with 2,531 patients with OC. An increased ALDH1 expression was shown to be predictive of poor prognosis and clinicopathological characteristics as a significant association was noted between increasing ALDH1 expression and International Federation of Gynecology and Obstetrics stage, lymph node metastasis, and distant metastasis in OC.