Breast cancer: Edited by Anne O. RodriguezCirculating tumor cells in breast cancerIgnatiadis, Michaila,b; Georgoulias, Vassilisa,b; Mavroudis, Dimitrisa,bAuthor Information aDepartment of Medical Oncology, University General Hospital of Heraklion, Greece bLaboratory of Tumor Cell Biology, School of Medicine, University of Crete, Crete, Greece Correspondence to Dimitris Mavroudis, MD, PhD, Department of Medical Oncology, University General Hospital of Heraklion, PO Box 1352, Heraklion 711 10, Crete, Greece Tel: +30 2810 392823; fax: +30 2810 392802; e-mail: [email protected] Current Opinion in Obstetrics and Gynecology: February 2008 - Volume 20 - Issue 1 - p 55-60 doi: 10.1097/GCO.0b013e3282f22b2e Buy Metrics Abstract Purpose of review To critically review the latest findings concerning the detection and characterization of circulating tumor cells in breast cancer. Recent findings 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. Summary 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. © 2008 Lippincott Williams & Wilkins, Inc.