title: Detection of Circulating Tumor Cells in Breast Cancer Patients Using Cytokeratin-19 Real-Time RT-PCR.
abstract: OBJECTIVE
  The roles of circulating tumor cells (CTCs) as predictive and prognostic factors, as well as key mediators in the metastatic cascade, have been investigated. This study aimed to validate a method to quantify CTCs in peripheral blood using a real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay for cytokeratin (CK)-19 and to evaluate the utility of this assay in detecting CTCs in breast cancer patients.
  
  
  METHODS
  Real-time monitoring PCR of fluorescently labeled specific hybridization probes for CK-19 mRNA was established. Peripheral blood samples from 30 healthy donors, 69 patients with early breast cancer, 47 patients with locally advanced breast cancer, and 126 patients with metastatic breast cancer were prospectively obtained and analyzed for CTC detection.
  
  
  RESULTS
  CK-19 mRNA was not detectable in healthy subjects using the real-time RT-PCR method. The detection rates of CK-19 mRNA in breast cancer patients were 47.8% for early breast cancer (33/69), 46.8% for locally advanced breast cancer (22/47), and 61.1% for metastatic breast cancer (77/129). The detection rate of CK-19-positive CTCs in metastatic disease was slightly higher than early or locally advanced breast cancer; however, the detection rate according to disease burden was not statistically different (p=0.097). The detection rate was higher in patients with pleural metastasis (p=0.045). CTC detection was associated with poor survival (p=0.014).
  
  
  CONCLUSIONS
  A highly specific and sensitive CK-19 mRNA-based method to detect CTCs in peripheral blood in breast cancer patients can be used in further prospective studies to evaluate the predictive and prognostic importance of CTCs.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyung Seok
authors.initials: HS
authors.lastname: Park
authors.affiliation: Avison Biomedical Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Han
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Soohyeon
authors.initials: S
authors.lastname: Lee
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Gun Min
authors.initials: GM
authors.lastname: Kim
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seho
authors.initials: S
authors.lastname: Park
authors.affiliation: Avison Biomedical Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yeon A
authors.initials: YA
authors.lastname: Choi
authors.affiliation: Avison Biomedical Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jeong Dong
authors.initials: JD
authors.lastname: Lee
authors.affiliation: Avison Biomedical Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Gi Moon
authors.initials: GM
authors.lastname: Kim
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea. oncosohn@yuhs.ac.
authors.forename: Joohyuk
authors.initials: J
authors.lastname: Sohn
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea. skim@yuhs.ac.
authors.forename: Seung Il
authors.initials: SI
authors.lastname: Kim
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood / Q000473:pathology*; D005260:Female; D006801:Humans; D053539:Keratin-19 / Q000097:blood* / Q000235:genetics; D009360:Neoplastic Cells, Circulating; D011379:Prognosis; D011446:Prospective Studies; D012333:RNA, Messenger / Q000097:blood*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
chemical_list: D014408:Biomarkers, Tumor; D053539:Keratin-19; D012333:RNA, Messenger
keywords: Cytokeratin-19 mRNA; RT-PCR; circulating tumor cells; metastatic breast cancer; peripheral blood samples