title: Circulating tumour markers can define patients with normal colons, benign polyps, and cancers.
abstract: BACKGROUND
  Early diagnosis represents the best opportunity for cure of colorectal cancer. Current screening programmes use faecal occult blood testing for screening, which has limited sensitivity and poor specificity.
  
  
  METHODS
  In this study we looked at a series of previously described diagnostic markers utilising circulating free DNA (cfDNA), with a preparation method allowing small DNA fragments to be isolated. The Circulating free DNA was isolated from samples obtained from 85 patients, including 35 patients without endoscopic abnormality, a group of 26 patients with benign colorectal adenomas, and 24 patients with colorectal carcinomas. In each case, polymerase chain reaction (PCR) was performed for Line1 79 bp, Line1 300 bp, Alu 115 bp, Alu 247 bp, and mitochondrial primers. In addition, carcinoembryonic antigen (CEA) was measured by ELISA. Each marker was analysed between normal, polyp, and cancer populations, and the best performing analysed in combination by logistic regression.
  
  
  RESULTS
  The best model was able to discriminate normal from populations with adenoma or carcinoma using three DNA markers and CEA, showing an area under the receiver operator characteristic (ROC) curve of 0.855 with a positive predictive value of 81.1% for polyps and cancer diagnosis.
  
  
  CONCLUSIONS
  These circulating markers in combination with other markers offer the prospect of a simple blood test as a possible secondary screen for colorectal cancers and polyps in patients with positive faecal occult blood tests.
authors.affiliation: Department of Gastroenterology and Translational Oncology Research Centre, Queen Alexandra Hospital, Portsmouth PO6 3LY, UK.
authors.forename: R
authors.initials: R
authors.lastname: Mead
authors.forename: M
authors.initials: M
authors.lastname: Duku
authors.forename: P
authors.initials: P
authors.lastname: Bhandari
authors.forename: I A
authors.initials: IA
authors.lastname: Cree
mesh_terms: D000236:Adenoma / Q000097:blood / Q000175:diagnosis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood* / Q000502:physiology; D002272:Carcinoembryonic Antigen / Q000032:analysis / Q000097:blood / Q000502:physiology; D002277:Carcinoma / Q000097:blood / Q000175:diagnosis*; D003106:Colon / Q000378:metabolism / Q000473:pathology; D003111:Colonic Polyps / Q000097:blood / Q000175:diagnosis*; D015179:Colorectal Neoplasms / Q000097:blood / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006262:Health; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen