Disseminated Tumor Cells and Cancer Stem Cells in Ovarian Cancer

Ovarian cancer is currently the fifth most lethal malignancy of women in Europe and the United States [1, 2]. The prognosis of ovarian cancer patients is limited due to lack of specific early symptoms and a high rate of relapse; more than half of all patients will suffer from disease recurrence, resulting in a poor overall survival [3]. Most cases are di‐ agnosed in advanced stages, and although the initial response to chemotherapy is gener‐ ally good, a significant proportion of patients will suffer from a relapse despite optimal cytoreductive surgery [4]. Since treatment strategies are mainly developed to control lo‐ coregional cancer growth, it may be anticipated that more women will die of distant metastatic disease. The identification of novel molecular markers, reflecting current tu‐ mor activity, may improve prediction and therapy monitoring and provide valuable in‐ sights into process of carcinogenesis. In this regard, oncologic research have increasingly focused on disseminated and circulating tumor cells.