title: Serum free circulating DNA is a useful biomarker to distinguish benign versus malignant prostate disease.
abstract: BACKGROUND
  Free circulating DNA (fcDNA) has been shown to be elevated in serum of prostate cancer patients compared with benign controls. However, studies evaluating the role of fcDNA as a biomarker in a "representative" patient group who have undergone prostate cancer screening are lacking. Our study examined the use of serum fcDNA levels as a biomarker of prostate cancer in such a setting.
  
  
  METHODS
  The study included 252 men, with prostate-specific antigen (PSA) levels >4 ng/mL and/or abnormal digital rectal exam. fcDNA levels in serum before prostate biopsy were quantitated by real-time PCR amplification of the glutathione S-transferase, pi, gene.
  
  
  RESULTS
  Patients with PSA < or = 10 ng/mL with fcDNA > 180 ng/mL were at increased risk for prostate cancer compared with those with fcDNA < or =180 ng/mL (odds ratio, 4.27; 95% confidence interval, 2.05-8.88; P < 0.001; area under the curve, 0.742). The multivariate model including age, race, PSA, fcDNA, and interaction between fcDNA and PSA yielded a high negative predictive value of 93.1% and increased specificity of 33.1% compared with negative predictive value of 73.3% and specificity of 6.7% in the model excluding fcDNA.
  
  
  CONCLUSIONS
  Our results indicate that fcDNA may improve the specificity of prostate cancer screening.
  
  
  CONCLUSIONS
  Our study shows that adding fcDNA to prostate cancer screening can reduce the number of unnecessary prostate biopsies.
authors.affiliation: Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, 1475 N.W. 12th Avenue, Miami, FL 33136, USA.
authors.forename: Edna
authors.initials: E
authors.lastname: Gordian
authors.forename: Kavitha
authors.initials: K
authors.lastname: Ramachandran
authors.forename: Isildinha M
authors.initials: IM
authors.lastname: Reis
authors.forename: Murugesan
authors.initials: M
authors.lastname: Manoharan
authors.forename: Mark S
authors.initials: MS
authors.lastname: Soloway
authors.forename: Rakesh
authors.initials: R
authors.lastname: Singal
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D001706:Biopsy / Q000706:statistics & numerical data; D004247:DNA / Q000097:blood*; D055088:Early Detection of Cancer; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology; D012306:Risk; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D004247:DNA; D017430:Prostate-Specific Antigen