title: CD99/MIC-2 surface protein expression in breast carcinomas.
abstract: OBJECTIVE
  To evaluate the expression of CD99/MIC-2 surface protein in invasive breast carcinomas and demonstrate whether or not there is a relationship with tumour phenotype.
  
  
  RESULTS
  Thirty-five invasive breast carcinomas, including five metaplastic carcinomas, were stained with CD99 primary antibodies using standard protocols based on streptavidin-biotin-peroxidase method. Four out of five metaplastic carcinomas expressed CD99/MIC-2 protein, three of them were matrix-producing carcinomas. From the other 30 cases, only an invasive apocrine carcinoma was positive. There was no statistical correlation between CD99 expression and the parameters analysed (histological typing and grading, proliferative index and nodal status).
  
  
  CONCLUSIONS
  CD99/MIC-2 is expressed in breast carcinomas, especially in the matrix-producing variant of metaplastic carcinomas, which impairs its use as a marker to differentiate metaplastic carcinomas from primary and metastatic sarcomas of the breast. It seems to have no prognostic implications. However, phenotype similarities with other chondromyxoid tumours that also express the protein, like mesenchymal chondrosarcomas, suggest a relationship between MIC-2 reactivity and morphological differentiation.
authors.affiliation: Institute of Pathology and Molecular Immunology of Porto University (IPATIMUP), Rua Dr Roberto Frias, s/n 4200 Porto, Portugal.
authors.forename: F
authors.initials: F
authors.lastname: Milanezi
authors.forename: E M
authors.initials: EM
authors.lastname: Pereira
authors.forename: F V
authors.initials: FV
authors.lastname: Ferreira
authors.forename: D
authors.initials: D
authors.lastname: Leitão
authors.forename: F C
authors.initials: FC
authors.lastname: Schmitt
mesh_terms: D000071443:12E7 Antigen; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000096:biosynthesis*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules