title: Prognostic significance of disseminated tumor cells as detected by quantitative real-time reverse-transcriptase polymerase chain reaction in patients with breast cancer.
abstract: BACKGROUND
  In this study we have validated the feasibility of detecting disseminated tumor cells (DTC) by real-time reverse-transcriptase polymerase chain reaction (RT-PCR) analysis. Bone marrow samples from a large cohort of patients with breast cancer were analyzed for the presence of DTC by immunocytochemistry (ICC) or a molecular-based method.
  
  
  METHODS
  Bone marrow samples were collected from 170 patients with breast cancer with stage I-IV disease before the initiation of any local or systemic treatment. Staining for cytokeratin (CK)-positive cells was performed with the Epimet kit. Disseminated tumor cells were also quantified by measuring relative gene expression for CK19 and mammaglobin (MAM) using a quantitative RT-PCR detection method. The mean follow-up time was 30 months. Kaplan-Meier analysis was used for predicting overall survival.
  
  
  RESULTS
  Despite an excellent quantitative correlation and qualitative concordance between ICC and RT-PCR, survival analysis suggested an improved prognostic significance of DTC as detected by quantitative RT-PCR. Univariate survival analysis computed a relative risk of death of 2.87 for women with ICC-positive cells in the bone marrow, as compared with those without positive cells. The relative risk for women with RT-PCR-positive bone marrow was even higher: 3.5 (CK19) and 3.39 (MAM). In multivariate analysis, bone marrow CK19 was a stronger prognostic factor than bone marrow ICC.
  
  
  CONCLUSIONS
  Reverse-transcriptase polymerase chain reaction-detected DTC is shown to be prognostically significant in untreated patients with breast cancer. Furthermore, it seems to be a more sensitive method for detecting DTC in bone marrow samples when compared with ICC.
authors.affiliation: Translational Cancer Research Group Antwerp, Wilrijk, Belgium.
authors.forename: Ina H
authors.initials: IH
authors.lastname: Benoy
authors.forename: Hilde
authors.initials: H
authors.lastname: Elst
authors.forename: Marita
authors.initials: M
authors.lastname: Philips
authors.forename: Hilde
authors.initials: H
authors.lastname: Wuyts
authors.forename: Peter
authors.initials: P
authors.lastname: Van Dam
authors.forename: Simon
authors.initials: S
authors.lastname: Scharpé
authors.forename: Eric
authors.initials: E
authors.lastname: Van Marck
authors.forename: Peter B
authors.initials: PB
authors.lastname: Vermeulen
authors.forename: Luc Y
authors.initials: LY
authors.lastname: Dirix
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019046:Bone Marrow Neoplasms / Q000556:secondary*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000235:genetics / Q000378:metabolism; D060785:Mammaglobin A; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D009360:Neoplastic Cells, Circulating; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014598:Uteroglobin / Q000235:genetics / Q000378:metabolism
chemical_list: D060785:Mammaglobin A; D009363:Neoplasm Proteins; D012333:RNA, Messenger; C556448:SCGB2A2 protein, human; D007633:Keratins; D014598:Uteroglobin