title: Serum osteoprotegerin levels are increased in patients with advanced prostate cancer.
abstract: OBJECTIVE
  Osteoprotegerin (OPG) is a soluble osteoclastogenesis inhibitor that regulates bone turnover. We reported recently that OPG protein expression is significantly increased in prostate cancer (CaP) cells present in bone metastases. The aim of this study was to determine serum OPG levels in patients at different stages of CaP and correlate the results with disease status.
  
  
  METHODS
  OPG levels were examined in patients with benign prostatic hyperplasia, clinically localized CaP, early recurrence of CaP, and advanced CaP and evidence of bone metastases. Serum OPG levels were measured by sandwich ELISA assays. The serum Crosslaps (sCTX) assay was used to quantify bone resorption in the advanced CaP group.
  
  
  RESULTS
  Serum OPG levels were increased significantly in the advanced CaP group versus all other groups. There was no significant correlation between serum OPG levels and PSA levels either in the advanced CaP group or within any of three treatment subclasses of this group: no Tx, those not treated; Tx, those treated; and R, those treated with resorption blockers. Levels of OPG were negatively correlated with sCTX levels only in the advanced CaP Tx group. sCTX levels correlated with prostate-specific antigen levels in the advanced CaP Tx and R groups but not in the no-Tx group.
  
  
  CONCLUSIONS
  Our data show that serum OPG levels are increased with advanced CaP. We hypothesize that OPG levels are related to CaP progression and suggest that further studies of the biological effects of OPG on CaP metastases are warranted.
authors.affiliation: Department of Urology, University of Washington, Seattle, 98195, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Brown
authors.forename: R L
authors.initials: RL
authors.lastname: Vessella
authors.forename: P J
authors.initials: PJ
authors.lastname: Kostenuik
authors.forename: C R
authors.initials: CR
authors.lastname: Dunstan
authors.forename: P H
authors.initials: PH
authors.lastname: Lange
authors.forename: E
authors.initials: E
authors.lastname: Corey
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000097:blood / Q000556:secondary; D003094:Collagen / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000473:pathology; D053244:Osteoprotegerin; D010446:Peptide Fragments / Q000097:blood; D011470:Prostatic Hyperplasia / Q000097:blood / Q000473:pathology; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000097:blood*; D018124:Receptors, Tumor Necrosis Factor
chemical_list: D006023:Glycoproteins; D053244:Osteoprotegerin; D010446:Peptide Fragments; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C506030:TNFRSF11B protein, human; C110762:glutamyl-lysyl-alanyl-histidyl-aspartyl-glycyl-glycyl-arginine; D003094:Collagen