title: Circulating DNA is a non-invasive prognostic factor for survival in non-small cell lung cancer.
abstract: BACKGROUND
  Circulating plasma DNA is present in a considerably higher concentration in lung cancer patients than in controls. Conflicting data are reported about circulating DNA as a prognostic factor. The aim of this study was to prospectively analyse the relationship of circulating plasma DNA with overall survival (OS) of previously untreated non-small cell lung cancer (NSCLC) patients.
  
  
  METHODS
  46 untreated NSCLC patients and 21 controls with a follow-up time of 6.5 years were analyzed. Quantification of baseline circulating plasma DNA was performed by a real-time quantitative polymerase chain reaction (qPCR) targeting the human beta-globin gene. Survival analysis was performed using the Kaplan-Meier method and compared with a Cox-regression analysis.
  
  
  RESULTS
  The median DNA concentration of the patients who died (87%) was significantly higher compared to the patients that survived at the end of follow-up (55ng/ml versus 23ng/ml, p=0.02). In patients with higher DNA concentration overall survival was significantly worse. In this study no relation of DNA concentration with tumour characteristics, age, gender or pulmonary inflammatory conditions was found.
  
  
  CONCLUSIONS
  In this study a high circulating plasma DNA concentration at time of diagnosis in NSCLC patients was a prognostic factor for poorer survival. Circulating DNA may be used as a non-invasive biomarker to refine the prognostic profile in NSCLC patients.
authors.affiliation: Department of Pulmonology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. m.vanderdrift@ulc.umcn.nl
authors.forename: Miep A
authors.initials: MA
authors.lastname: van der Drift
authors.forename: Bernard E A
authors.initials: BE
authors.lastname: Hol
authors.forename: Corné H W
authors.initials: CH
authors.lastname: Klaassen
authors.forename: Clemens F M
authors.initials: CF
authors.lastname: Prinsen
authors.forename: Yvonne A W G
authors.initials: YA
authors.lastname: van Aarssen
authors.forename: Rogier
authors.initials: R
authors.lastname: Donders
authors.forename: Jos W J
authors.initials: JW
authors.lastname: van der Stappen
authors.forename: P N Richard
authors.initials: PN
authors.lastname: Dekhuijzen
authors.forename: Henricus F M
authors.initials: HF
authors.lastname: van der Heijden
authors.forename: Frederik B J M
authors.initials: FB
authors.lastname: Thunnissen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D004247:DNA / Q000097:blood*; D004273:DNA, Neoplasm / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis
chemical_list: D004273:DNA, Neoplasm; D004247:DNA