title: Phenotypic characterization of circulating tumor cells in triple negative breast cancer patients.
abstract: BACKGROUND
  Patients with triple negative breast cancer (TNBC), are considered as a poor prognosis group for whom no targeted therapies are currently available. The aim of the present study was to phenotypically characterize their CTCs in order to explore potential therapeutic targets.
  
  
  METHODS
  PBMC's cytospins were prepared from 45 early (before and after adjuvant chemotherapy), 10 metastatic TNBC and 21 hormone receptor (HR) -positive patients. The expression of Cytokeratins (CK), ER, PR, EGFR and HER2 on CTCs was assessed using immunofluoresence staining and ARIOL analysis.
  
  
  RESULTS
  In early stage TNBC, ER, PR, HER2 and EGFR expressing-CTCs were detected in 24.4%, 24.4%, 20% and 40% of patients before the initiation of adjuvant chemotherapy, and in 17.8%, 13.3% 6.7% and 51.1% respectively after the completion of adjuvant treatment. Triple staining experiments revealed distinct subpopulations of CTC expressed HR, and ErbB family receptors. In patients with metastatic disease, the frequency of HER2+ CTCs was significantly increased compared to adjuvant setting (60% vs 20%, p=0.014). The presence of CK+PR- CTCs, before adjuvant treatment was associated with reduced OS (p=0.032) and DFI (p=0.04). Furthermore, the frequency of ER-, PR- and HER2+ CTCs was higher in HR(+) than in TNBC tumors (57.1%, p=0.006; 52.4%, p=0.021 and 52.38%, p=0.009, respectively).
  
  
  CONCLUSIONS
  The CTCs in patients with early TNBC are phenotypically heterogeneous based on the expression of HR, EGFR and HER2 both before and after the completion of adjuvant chemotherapy whereas the presence of HER2+ CTCs prevails during disease evolution. These findings could be of clinical relevance in terms of CTC targeting.
authors.affiliation: Laboratory of Translational Oncology, School of Medicine, University of Crete, Voutes, Heraklion, Greece.|Department of Medical Oncology, University General Hospital of Heraklion, Voutes, Heraklion, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Agelaki
authors.affiliation: Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Voutes, Heraklion, Greece.
authors.forename: Melina
authors.initials: M
authors.lastname: Dragolia
authors.affiliation: Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Voutes, Heraklion, Greece.
authors.forename: Harris
authors.initials: H
authors.lastname: Markonanolaki
authors.affiliation: Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia.|Department of Biochemistry, University of Crete Medical School, Voutes, Heraklion, Greece.
authors.forename: Saad
authors.initials: S
authors.lastname: Alkahtani
authors.affiliation: Department of Biochemistry, University of Crete Medical School, Voutes, Heraklion, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Stournaras
authors.affiliation: Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Voutes, Heraklion, Greece.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Georgoulias
authors.affiliation: Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Voutes, Heraklion, Greece.|Department of Biochemistry, University of Crete Medical School, Voutes, Heraklion, Greece.
authors.forename: Galatea
authors.initials: G
authors.lastname: Kallergi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D045744:Cell Line, Tumor; D017024:Chemotherapy, Adjuvant; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D007633:Keratins / Q000378:metabolism; D061986:MCF-7 Cells; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000378:metabolism*; D010641:Phenotype; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D064726:Triple Negative Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism
chemical_list: D066246:ErbB Receptors; D007633:Keratins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C512478:EGFR protein, human; C508053:ERBB2 protein, human
keywords: CTCs; EGFR; HER2; estrogen receptor; progesteron receptor