title: Circulating tumor cells in breast cancer.
abstract: OBJECTIVE
  To critically review the latest findings concerning the detection and characterization of circulating tumor cells in breast cancer.
  
  
  RESULTS
  Various studies have used different methods and markers for circulating tumor cell detection in breast cancer. Data on the prognostic value of circulating tumor cell monitoring by the CellSearch system are now available in patients with measurable metastatic breast cancer receiving chemotherapy, whereas no such data are still available for adjuvant or neoadjuvant settings. The detection of cytokeratin 19 mRNA-positive cells before the initiation of adjuvant chemotherapy was shown to be an independent prognostic factor for worse clinical outcome in patients with early breast cancer. Interestingly, this was mainly observed in patients with triple-negative and HER2-positive, but not estrogen receptor-positive/HER2-negative, early breast cancer. Finally, gene-expression profiling of single cells was reported to be feasible with important implications for eliminating circulating tumor cells. Pilot studies have shown that phenotyping of circulating tumor cells could be used to predict response to targeted therapies.
  
  
  CONCLUSIONS
  Circulating tumor cells might become a valuable tool to refine prognosis in early and metastatic breast cancer. Circulating tumor cell phenotyping/profiling may serve as a real-time tumor biopsy for individually-tailored targeted therapies.
authors.affiliation: Department of Medical Oncology, University General Hospital of Heraklion, Heraklion, Crete, Greece.
authors.forename: Michail
authors.initials: M
authors.lastname: Ignatiadis
authors.forename: Vassilis
authors.initials: V
authors.lastname: Georgoulias
authors.forename: Dimitris
authors.initials: D
authors.lastname: Mavroudis
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006801:Humans; D018189:Immunomagnetic Separation; D053539:Keratin-19 / Q000097:blood*; D009360:Neoplastic Cells, Circulating; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011379:Prognosis; D012334:RNA, Neoplasm / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D053539:Keratin-19; D012334:RNA, Neoplasm