title: Detecting prostate cancer by intracellular macrophage prostate-specific antigen (PSA): a more specific and sensitive marker than conventional serum total PSA.
abstract: BACKGROUND
  Serum prostate-specific antigen (PSA) is a standard method and a widely used marker for prostate cancer, but it has a poor specificity for early detection. Herein we demonstrate that intracellular macrophage PSA (imPSA) enables screening and differentiation between benign and malignant prostate disease.
  
  
  METHODS
  The efficacy of intracellular macrophage PSA in circulating and tissue macrophages was therefore investigated in a double-centre study of 38 prostate cancer patients and 36 healthy controls by fluorescent-activated cell sorting analysis and immunohistology.
  
  
  RESULTS
  Both methods uncovered the existence of PSA-positive macrophages specific for patients with prostate cancer. In addition, we demonstrate the superiority of our new test over standard serum total PSA in a blinded double-centre trial. ImPSA had a marked higher sensitivity and specificity than serum total PSA (imPSA: sensitivity 92%, specificity 92%, positive predictive value 92%; serum total PSA: sensitivity 79.5%, specificity 87.5%, positive predictive value 26.8%).
  
  
  CONCLUSIONS
  In this study, we demonstrate that imPSA is a new prostate cancer screening method that is highly sensitive and more specific than standard PSA testing.
authors.affiliation: Department of Urology, Medical University Vienna, Vienna, Austria. ralf.herwig@meduniwien.ac.at
authors.forename: R
authors.initials: R
authors.lastname: Herwig
authors.forename: D
authors.initials: D
authors.lastname: Mitteregger
authors.forename: B
authors.initials: B
authors.lastname: Djavan
authors.forename: G
authors.initials: G
authors.lastname: Kramer
authors.forename: M
authors.initials: M
authors.lastname: Margreiter
authors.forename: M P
authors.initials: MP
authors.lastname: Leers
authors.forename: B
authors.initials: B
authors.lastname: Glodny
authors.forename: D G
authors.initials: DG
authors.lastname: Haider
authors.forename: W H
authors.initials: WH
authors.lastname: Hörl
authors.forename: M
authors.initials: M
authors.lastname: Marberger
mesh_terms: D000328:Adult; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000032:analysis*; D016022:Case-Control Studies; D022162:Cytoplasmic Vesicles / Q000737:chemistry*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000737:chemistry*; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011470:Prostatic Hyperplasia / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000737:chemistry*; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen