title: Expression of RANKL/RANK/OPG in primary and metastatic human prostate cancer as markers of disease stage and functional regulation.
abstract: BACKGROUND
  Late-stage prostate cancer patients are refractory to hormone therapy and exhibit a high propensity to develop skeletal metastasis. In this regard, the role of a novel cytokine system belonging to the tumor necrosis factor (TNF) family that is critical for osteoclastic osteolysis and that consists of receptor activator of NF-kappaB ligand (RANKL), its receptor (RANK), and decoy receptor osteoprotegerin (OPG) is of potential interest.
  
  
  METHODS
  Reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohistochemical analysis was used to examine the expression of RANKL, RANK, and OPG in human prostate cancer cell lines and in 89 archival samples of primary and metastatic (lymph nodes, skeleton) prostate cancer patients. Expression of these proteins was correlated with clinicopathogic parameters of the prostate cancer.
  
  
  RESULTS
  Expression of RANKL/RANK/OPG was low in normal but markedly higher in prostate cancer cell lines. Analysis of surgical biopsy specimens showed the expression of RANKL (31%), RANK (38%), and OPG (19%) in primary carcinoma. The expression frequency was significantly higher (RANKL [44%], RANK [49%], and OPG [73%]) in metastatic prostate cancer. OPG (83%) production was more common in skeletal as compared with lymph node metastases (46%), whereas the expression of RANKL expression was less discordant in bone (47%) and lymph node metastases (36%). The increased expression of RANKL/RANK/OPG observed correlated with Gleason score, TNM stage, androgen status, and serum prostate-specific antigen (PSA) levels in the prostate cancer patients.
  
  
  CONCLUSIONS
  Expression of RANKL/RANK/OPG correlates with more aggressive, advanced, metastatic prostate carcinoma to suggest their role as diagnostic, prognostic, and therapeutic targets for prostate cancer.
authors.affiliation: Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada.
authors.forename: Gaoping
authors.initials: G
authors.lastname: Chen
authors.forename: Kanishka
authors.initials: K
authors.lastname: Sircar
authors.forename: Armen
authors.initials: A
authors.lastname: Aprikian
authors.forename: Anil
authors.initials: A
authors.lastname: Potti
authors.forename: David
authors.initials: D
authors.lastname: Goltzman
authors.forename: Shafaat A
authors.initials: SA
authors.lastname: Rabbani
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002277:Carcinoma / Q000175:diagnosis / Q000378:metabolism / Q000556:secondary*; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006023:Glycoproteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D053244:Osteoprotegerin; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D017430:Prostate-Specific Antigen