title: Circulating tumor cell detection in advanced non-small cell lung cancer patients by multi-marker QPCR analysis.
abstract: BACKGROUND
  The aim of this study was to explore circulating tumor cell (CTC) detection in advanced non-small cell lung cancer (NSCLC). CTCs may not only serve as a prognostic marker in selected tumor types, but may also be useful as pharmacodynamic marker in drug development.
  
  
  METHODS
  Fourty-six advanced NSCLC patients and fourty-six healthy controls were included in the study and 8.0 ml of peripheral blood was obtained from each of the participants. Immunomagnetic bead enrichment for cells expressing epithelial cell adhesion molecule (EpCAM) was performed, followed by multi-marker quantitative real-time PCR of a panel of marker genes: cytokeratin 7 (CK7), cytokeratin 19 (CK19), human epithelial glycoprotein (EGP) and fibronectin 1 (FN1). Using quadratic discriminant analysis (QDA), expression values were combined into a single score, which indicated CTC-positivity or -negativity. Test characteristics were assessed using receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  ROC curve analysis showed capability of discrimination between advanced NSCLC patients and healthy controls (area=0.712; 95% CI 0.606-0.819; P<0.001). A cut-off minimizing overall misclassification for QDA-positivity reached a sensitivity of 46% (95% CI 31-61) and a specificity of 93% (95% CI 82-99).
  
  
  CONCLUSIONS
  In this exploratory study, an assay was developed for discriminating CTCs in peripheral blood samples of advanced NSCLC patients from healthy controls. The assay demonstrated an acceptable sensitivity in combination with good specificity. Further validation studies should take place in NSCLC patients and a matched control group.
authors.affiliation: Division of Experimental Therapy, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
authors.forename: L A
authors.initials: LA
authors.lastname: Devriese
authors.forename: A J
authors.initials: AJ
authors.lastname: Bosma
authors.forename: M M
authors.initials: MM
authors.lastname: van de Heuvel
authors.forename: W
authors.initials: W
authors.lastname: Heemsbergen
authors.forename: E E
authors.initials: EE
authors.lastname: Voest
authors.forename: J H M
authors.initials: JH
authors.lastname: Schellens
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology*; D005260:Female; D005353:Fibronectins / Q000032:analysis; D006801:Humans; D053539:Keratin-19 / Q000032:analysis; D053552:Keratin-7 / Q000032:analysis; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating; D010865:Pilot Projects; D012372:ROC Curve; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012907:Smoking / Q000378:metabolism
chemical_list: C067625:FN1 protein, human; D005353:Fibronectins; D053539:Keratin-19; D053552:Keratin-7