title: α-methylacyl-CoA racemase (AMACR) expression in chordomas differentiates them from chondrosarcomas.
abstract: OBJECTIVE
  Chordomas and chondrosarcomas are malignant mesenchymal tumours with overlapping morphological and immunohistochemical (IHC) characteristics. Our aim was to evaluate the IHC expression of α-methylacyl-CoA racemase (AMACR/P504S), β-catenin and E-cadherin in chordomas relative to chondrosarcomas and assess the utility of these markers for differential diagnosis.
  
  
  METHODS
  Archival sections of 18 chordomas, 19 chondrosarcomas and 10 mature cartilage samples were immunostained and scored for AMACR, β-catenin and E-cadherin and the relative differential capacity of each marker was calculated. In addition, AMACR mRNA level was assessed in 5 chordomas by RT-PCR and evaluated by comparative CT method.
  
  
  RESULTS
  AMACR and β-catenin stained 88.9% and 94.1% of the chordomas respectively, 21.1% and 10.5% of the chondrosarcomas correspondingly and none of the mature cartilage samples. E-cadherin stained positively 82.4% of the chordomas, 36.8% of the chondrosarcomas and 42.9% of the mature cartilage cases. Both AMACR and β-catenin showed statistically significant difference between chordomas and chondrosarcomas (p < 0.001 for both), unlike E-cadherin. AMACR was detected at the mRNA level.
  
  
  CONCLUSIONS
  AMACR is expressed in most of the chordomas but only in a minority of chondrosarcomas. AMACR may serve as IHC marker of chordoma with differentiating ability comparable to that of β-catenin.
authors.affiliation: Department of Pathology, Sheba Medical Center, 52621 Tel Hashomer, Israel.|Talpiot Medical Leadership Program, Sheba Medical Center, Israel.
authors.forename: Sarit
authors.initials: S
authors.lastname: Aviel-Ronen
authors.affiliation: Department of Pathology, Sheba Medical Center, 52621 Tel Hashomer, Israel.
authors.forename: Oranit
authors.initials: O
authors.lastname: Zadok
authors.affiliation: Department of Statistics and Operations Research, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Aya
authors.initials: A
authors.lastname: Vituri
authors.affiliation: Department of Pathology, Sheba Medical Center, 52621 Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Dvora
authors.initials: D
authors.lastname: Nass
authors.affiliation: Department of Pathology, Sheba Medical Center, 52621 Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ignat
authors.initials: I
authors.lastname: Schwartz
authors.affiliation: Department of Pathology, Sheba Medical Center, 52621 Tel Hashomer, Israel.
authors.forename: Camila
authors.initials: C
authors.lastname: Avivi
authors.affiliation: Department of Pathology, Sheba Medical Center, 52621 Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Iris
authors.initials: I
authors.lastname: Barshack
mesh_terms: D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D002356:Cartilage / Q000201:enzymology / Q000473:pathology; D002812:Chondroma / Q000201:enzymology* / Q000473:pathology; D002813:Chondrosarcoma / Q000201:enzymology* / Q000473:pathology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D019998:Racemases and Epimerases / Q000096:biosynthesis*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D019998:Racemases and Epimerases; C108352:alpha-methylacyl-CoA racemase