title: Cytokeratin-based CTC counting unrelated to clinical follow up.
abstract: BACKGROUND
  Circulating tumor cells (CTCs) have been reported to be a relevant prognostic biomarker in metastatic patients. However, their clinical use and impact is still under debate. We have thus comparatively and kinetically assessed two CTC detection methods according to the patient's clinical follow up.
  
  
  METHODS
  CTC counting and characterization were repeatedly performed during follow up in a patient with metastatic undifferentiated non-small cell lung cancer by using cytokeratin (CK)-dependent immunomagnetic separation (Miltenyi) and CK-independent, size-based isolation [isolation by size of tumor cells (ISET)] (Rarecells).
  
  
  RESULTS
  Comparison between the two methods showed a parallel increase of CTC detected by ISET and worsening of the clinical status, while CK-dependent CTC numbers were decreasing, misleadingly suggesting a response to treatment. ISET results were in agreement with the clinical follow up showing Circulating tumor microemboli (CTM) and CTC expressing a mesenchymal marker with absence of epithelial markers.
  
  
  CONCLUSIONS
  This case report study shows the interest of a comparative and kinetic analysis of different methods for CTCs detection combined with their evaluation according to the clinical follow up. Our results should open up an area for future research and validation in larger clinical cohorts.
authors.affiliation: Department of Anatomic Pathology, AC Camargo Cancer Hospital, São Paulo, Brazil; ; Department of Clinical Oncology, AC Camargo Cancer Hospital, São Paulo, Brazil;
authors.forename: Ludmilla Thomé Domingos
authors.initials: LT
authors.lastname: Chinen
authors.forename: Fernanda Machado
authors.initials: FM
authors.lastname: de Carvalho
authors.forename: Bruna Maria Malagoli
authors.initials: BM
authors.lastname: Rocha
authors.forename: Caroline Motta
authors.initials: CM
authors.lastname: Aguiar
authors.forename: Emne Ali
authors.initials: EA
authors.lastname: Abdallah
authors.forename: Daniel
authors.initials: D
authors.lastname: Campanha
authors.forename: Natália Breve
authors.initials: NB
authors.lastname: Mingues
authors.forename: Thiago Bueno
authors.initials: TB
authors.lastname: de Oliveira
authors.forename: Macello Sampaio
authors.initials: MS
authors.lastname: Maciel
authors.forename: Gustavo Marchioro
authors.initials: GM
authors.lastname: Cervantes
authors.forename: Aldo L A
authors.initials: AL
authors.lastname: Dettino
authors.forename: Fernando Augusto
authors.initials: FA
authors.lastname: Soares
authors.forename: Patrizia
authors.initials: P
authors.lastname: Paterlini-Bréchot
authors.forename: Marcello Ferretti
authors.initials: MF
authors.lastname: Fanelli
keywords: Circulating tumor cells (CTCs); circulating tumor microemboli (CTM); immunomagnetic separation; isolation by size of tumor cells (ISET); lung cancer