Epithelial ovarian cancer stem cells-a review.

Ovarian cancer is the fifth leading cause of cancer deaths among women and the most common type of gynecologic malignancy. Despite advances in surgery and chemotherapy, the survival rate of patients with epithelial ovarian cancer is still low. For a whole decade, that situation has not improved. Most ovarian cancer patients relapse and become drug-resistant. Increasing evidence has suggested that tumor growth capability is dependent upon cancer stem cells (CSCs) that represent a small subset of cells within a variety of human tumors. In immunocompromised mice, CSCs were assayed by their ability to initiate tumor growth. Although still being explored, the ovarian CSCs, which have been found in several ovarian cancer cell lines, are within a mixed population of cells derived from the ascites of a patient with advanced ovarian cancer. Hope may lie in killing of the ovarian CSCs. They are also likely to be the therapeutic target in the treatment of epithelial ovarian cancer. Thus, a thorough understanding of CSCs' biology, particularly of how they differ from ordinary cancer cells and normal stem cells, might lead to a more effective ovarian cancer therapeutic strategy involving the selective targeting and elimination of ovarian CSCs.