title: [Importance of the tumor stem cell hypothesis for understanding ovarian cancer].
abstract: BACKGROUND
  Despite complex surgical and systemic therapies epithelial ovarian cancer has a poor prognosis. A small quantity of tumorigenic cells termed cancer stem cells (CSC) are responsible for the development of chemoresistance and high rates of recurrence.
  
  
  OBJECTIVE
  This review presents the CSC hypothesis and describes methods of identification and enrichment of CSCs as well as approaches for the therapeutic use of these findings.
  
  
  METHODS
  A systematic literature review based on PubMed and Web of Science was carried out.
  
  
  RESULTS
  The CSC model is based on a hierarchical structure of tumors with few CSCs and variably differentiated tumor cells constituting the tumor bulk. Only the CSCs possess tumorigenic potential. Other essential functional characteristics of CSCs are their potential for self-renewal and their ability to differentiate into further cell types. The CSCs are structurally characterized by different surface markers and changes in certain signaling pathways. Currently there are phase I and II studies in progress investigating specific influences on CSCs.
  
  
  CONCLUSIONS
  Various clinical characteristics of the course of disease in ovarian cancer are aptly represented by the tumor stem cell model. In spite of precisely defined functional characteristics of CSCs, surface markers and signaling pathways show individual differences and vary between tumor entities. This complicates identification and enrichment. Current experimental findings in various approaches and even first clinical studies raise hopes for a personalized cancer therapy targeting CSCs.
authors.affiliation: Zentrum für Frauen- und Kindermedizin, Gynäkologische Onkologie, Universitätsfrauenklinik Leipzig, Liebigstr. 20a, 04103, Leipzig, Deutschland.
authors.forename: R
authors.initials: R
authors.lastname: Vochem
authors.forename: J
authors.initials: J
authors.lastname: Einenkel
authors.forename: L-C
authors.initials: LC
authors.lastname: Horn
authors.forename: P
authors.initials: P
authors.lastname: Ruschpler
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000032:analysis; D002278:Carcinoma in Situ / Q000473:pathology* / Q000628:therapy; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000628:therapy; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000473:pathology* / Q000628:therapy; D010053:Ovary / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor