title: Discrimination of men with prostate cancer from those with benign disease by measurements of human glandular kallikrein 2 (HK2) in serum.
abstract: OBJECTIVE
  To investigate the clinical value of measuring human glandular kallikrein 2 (hK2) compared with free and total prostate specific antigen (PSA-F and PSA-T) in serum from patients with prostate disease.
  
  
  METHODS
  Serum from healthy controls, from men with benign prostate hyperplasia (BPH), clinically localized prostate cancer (PCa), and advanced PCa were analyzed for hK2 (using an in-house-research assay with detection limit of 0.05 ng./mL and <0.1% cross-reaction with PSA) and for PSA-F and PSA-T (using the Dual Prostatus assay from EG&G Wallac).
  
  
  RESULTS
  HK2 concentrations were <0.05 ng./mL in 50/50 healthy volunteers but significantly higher (p <0.0001) and > or =0.05 ng./mL in 28/54 (52%) patients with BPH. In comparison to these men, the hK2 levels were significantly higher (p <0.0001, median 0.085 ng./mL) and > or =0.05 ng./mL in 100/136 (74%) men with clinically localized PCa. Compared with localized PCa, the hK2 levels were significantly higher (p <0.0001, median 0.57 ng./mL) and > or =0.05 ng./mL in 55/57 (96%) patients with advanced PCa. The median hK2 levels ranged from 1.3 to 1.6% of those of PSA-T in all three patient groups, whereas percent hK2/PSA-F and hK2 x PSA-T/PSA-F levels were significantly higher in cancer patients compared with those with BPH. In the discrimination of clinically localized PCa from BPH, hK2 x PSA-T/PSA-F gave the largest area under the receiver operating curve (AUC = 0.81) and significantly (p = 0.025) larger AUC than PSA-T alone (0.70). Further, at 95% sensitivity there was significant gain in specificity, and at specificity levels of 90 to 95% there was significant gain in sensitivity using the measurements of PSA-T+PSA-F+hK2 compared with analysis of PSA-T and/or percent free PSA.
  
  
  CONCLUSIONS
  Discrimination of patients with benign prostate disease from those with prostate cancer was significantly enhanced using measurements of hK2 in addition to those of PSA-T and PSA-F. Percent hK2/PSA-F was higher in PCa than in BPH, a phenomena not yet understood.
authors.affiliation: Department of Clinical Chemistry, Lund University, University Hospital Malmö, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Becker
authors.forename: T
authors.initials: T
authors.lastname: Piironen
authors.forename: K
authors.initials: K
authors.lastname: Pettersson
authors.forename: T
authors.initials: T
authors.lastname: Björk
authors.forename: K J
authors.initials: KJ
authors.lastname: Wojno
authors.forename: J E
authors.initials: JE
authors.lastname: Oesterling
authors.forename: H
authors.initials: H
authors.lastname: Lilja
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011470:Prostatic Hyperplasia / Q000097:blood* / Q000175:diagnosis*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D020840:Tissue Kallikreins / Q000097:blood*
chemical_list: D020840:Tissue Kallikreins; D017430:Prostate-Specific Antigen