title: Use of human glandular kallikrein 2 for the detection of prostate cancer: preliminary analysis.
abstract: OBJECTIVE
  Human glandular kallikrein 2 (hK2) and prostate-specific antigen (PSA) are members of a multigene family of serine proteases that share approximately 80% sequence homology. Both are expressed in the prostate epithelium, are under androgen regulation, are present in serum and seminal fluid, and can form complexes with endogenous protease inhibitors (eg, alpha2-macroglobulin and alpha1-antichymotrypsin). Differences in immunohistochemistry and substrate specificity suggest hK2 may provide unique information for early detection and characterization of prostate cancer.
  
  
  METHODS
  Nine hundred thirty-seven archived serum samples from men treated at two academic institutions were studied. All men underwent biopsy, had a histologically confirmed diagnosis of cancer or noncancer, and a total PSA level greater than 2 ng/mL. Samples were tested in Hybritech's Tandem-R PSA and Tandem-R free PSA (fPSA) assays and a research prototype assay for total hK2 (thK2).
  
  
  RESULTS
  The thK2/fPSA ratio provided additional specificity for cancer detection over PSA and the percentage of fPSA (%fPSA). A model for cancer detection using %fPSA and the thK2/fPSA ratio when PSA is 2 to 4 ng/mL is proposed that would identify as many as 40% of the cancers and would require biopsy in only 16.5% of the men in this PSA range.
  
  
  CONCLUSIONS
  In this study, %fPSA and thK2/fPSA provided unique information for prostate cancer detection and increased the specificity of cancer detection.
authors.affiliation: Department of Urology, Johns Hopkins Hospital, Baltimore, Maryland, USA.
authors.forename: A W
authors.initials: AW
authors.lastname: Partin
authors.forename: W J
authors.initials: WJ
authors.lastname: Catalona
authors.forename: J A
authors.initials: JA
authors.lastname: Finlay
authors.forename: C
authors.initials: C
authors.lastname: Darte
authors.forename: D J
authors.initials: DJ
authors.lastname: Tindall
authors.forename: C Y
authors.initials: CY
authors.lastname: Young
authors.forename: G G
authors.initials: GG
authors.lastname: Klee
authors.forename: D W
authors.initials: DW
authors.lastname: Chan
authors.forename: H G
authors.initials: HG
authors.lastname: Rittenhouse
authors.forename: R L
authors.initials: RL
authors.lastname: Wolfert
authors.forename: D L
authors.initials: DL
authors.lastname: Woodrum
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D020840:Tissue Kallikreins / Q000097:blood*
chemical_list: D020840:Tissue Kallikreins; D017430:Prostate-Specific Antigen