title: Free DNA and carcinoembryonic antigen serum levels: an important combination for diagnosis of colorectal cancer.
abstract: OBJECTIVE
  The identification of new molecular markers for the early detection of colorectal cancer has become an important objective. We compared the sensitivity and specificity of free circulating DNA with that of the more conventional carcinoembryonic antigen (CEA) and evaluated the two markers in combination.
  
  
  METHODS
  The study was carried out on 75 healthy donors and 75 colorectal cancer patients. Free DNA was determined in serum with quantitative PCR analysis. The diagnostic accuracy of each assay was calculated using receiver operating characteristic (ROC) curves. The diagnostic relevance of the two-marker combination was analyzed by the logistic regression model.
  
  
  RESULTS
  Median free DNA concentration was approximately 5-fold higher in patients than in healthy donors (P < 0.001). The area under the ROC curve was 0.86, and when 12.5 ng/mL was used as cutoff, 81.3% sensitivity and 73.3% specificity were observed for the overall series. As CEA and free DNA provided independent diagnostic information, they were also considered in combination. ROC curve analysis of the combined CEA and free DNA algorithms showed a higher diagnostic capacity (area under the ROC curve, 0.92) than that of markers considered singly, with 84% sensitivity and 88% specificity.
  
  
  CONCLUSIONS
  Free circulating DNA, especially when used in combination with CEA, represents a potentially useful tool for the diagnosis of early-stage colorectal cancer.
authors.affiliation: Department of Medical Oncology, Morgagni-Pierantoni Hospital, Forlì, Italy. e.flamini@ausl.fo.it
authors.forename: Emanuela
authors.initials: E
authors.lastname: Flamini
authors.forename: Laura
authors.initials: L
authors.lastname: Mercatali
authors.forename: Oriana
authors.initials: O
authors.lastname: Nanni
authors.forename: Daniele
authors.initials: D
authors.lastname: Calistri
authors.forename: Roberta
authors.initials: R
authors.lastname: Nunziatini
authors.forename: Wainer
authors.initials: W
authors.lastname: Zoli
authors.forename: Paola
authors.initials: P
authors.lastname: Rosetti
authors.forename: Nice
authors.initials: N
authors.lastname: Gardini
authors.forename: Arturo
authors.initials: A
authors.lastname: Lattuneddu
authors.forename: Giorgio Maria
authors.initials: GM
authors.lastname: Verdecchia
authors.forename: Dino
authors.initials: D
authors.lastname: Amadori
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D004247:DNA / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012044:Regression Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D004247:DNA