title: CD146 protein in prostate cancer: revisited with two different antibodies.
abstract: OBJECTIVE
  CD146 is a potentially metastasis promoting cell adhesion molecule and its expression has been described in various solid tumours. We aimed to evaluate the expression of CD146 in prostate cancer by immunohistochemistry in a clinically characterised study cohort to evaluate its prognostic properties.
  
  
  METHODS
  We evaluated the CD146 protein expression using a polyclonal and a monoclonal antibody on 169 clinico-pathologically characterised cases. Statistical analyses were applied to test for correlations and diagnostic and prognostic associations.
  
  
  RESULTS
  CD146 detection with the polyclonal antibody revealed marked differential expression between tumour and normal tissue and was also a significant marker for shortened PSA relapse free survival. The monoclonal CD146 antibody demonstrated a weaker epithelial signal, which was significantly correlated with that of the polyclonal antibody, but revealed no prognostic value. However, the Western blot of the polyclonal antibody displayed a clearly reduced specificity.
  
  
  CONCLUSIONS
  Evaluation of protein expression can be highly dependent on the primary antibody employed. A credible evaluation of antibody specificity is crucial to prove the validity of protein expression studies. The immunoreactivity of the polyclonal CD146 antibody (Abcam, ab28360) is prognostic of PSA-relapse in prostate cancer patients, although its immunoreactivity is possibly not restricted to CD146 associated epitopes.
authors.affiliation: Institute of Pathology, Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Florian Rudolf
authors.initials: FR
authors.lastname: Fritzsche
authors.forename: Kirsten
authors.initials: K
authors.lastname: Wassermann
authors.forename: Anja
authors.initials: A
authors.lastname: Rabien
authors.forename: Hanka
authors.initials: H
authors.lastname: Schicktanz
authors.forename: Anja
authors.initials: A
authors.lastname: Dankof
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Loening
authors.forename: Manfred
authors.initials: M
authors.lastname: Dietel
authors.forename: Klaus
authors.initials: K
authors.lastname: Jung
authors.forename: Glen
authors.initials: G
authors.lastname: Kristiansen
mesh_terms: D000906:Antibodies; D000918:Antibody Specificity; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D051929:CD146 Antigen / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology
chemical_list: D000906:Antibodies; D014408:Biomarkers, Tumor; D051929:CD146 Antigen; C497902:MCAM protein, human; D017430:Prostate-Specific Antigen