title: [Metaplastic carcinomas of the breast: a morphological and immunohistochemical study].
abstract: BACKGROUND
  Metaplastic carcinomas of the breast are rare and form a heterogenic group of tumors, characterized by the presence of squamous or sarcomatoid differentiation.
  
  
  METHODS
  In 23 cases, we study the main histoprognostic features, hormonal status, and the expression of HER2, CK5/6, CK14, p63, EGFR, beta-catenin, MUC1 and E-cadherin, the expression of this seven last antigens being also studied in nodal metastases.
  
  
  RESULTS
  The different metaplastic types are spindle cell carcinoma (35%), squamous cell carcinoma (26%), osteo- or chondrosarcomatoid (11%) or mixed type (26%). Vascular emboli are seen in 30% of the tumors and perinervous infiltration in 4%. 33% of the patients have nodal metastases. The immunohistochemical features are: RO+: 4%; RP+: 8%; HER2+: 0%; p63+: 74%; CK14+: 83%; CK5/6+: 74%; EGFR+: 100%; E-cadherin+: 70%; beta-catenin: aberrant staining (cytoplasm or weak membrane staining greater than 5%): 74%, negative: 13%; MUC1: aberrant staining (cytoplasm or complete membrane staining greater than 5%): 35%, pure partial membrane staining: 22%, negative: 43%. In 43% of tumors, more aberrant staining for MUCI is present in nodal metastases compared with primitive tumor.
  
  
  CONCLUSIONS
  Metaplastic carcinomas are aggressive tumors, generally with a "triple-negative" and basal phenotype. The expressions of MUC1 and beta-catenin are often absent or aberrant, which could favor metastatic dissemination.
authors.affiliation: Laboratoire de pathologie, centre Alexis-Vautrin, Vandœuvre-lès-Nancy, France. g.gauchotte@yahoo.fr
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gauchotte
authors.forename: Emilie
authors.initials: E
authors.lastname: Gauchotte
authors.forename: Aude
authors.initials: A
authors.lastname: Bressenot
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Verhaeghe
authors.forename: François
authors.initials: F
authors.lastname: Guillemin
authors.forename: Agnès
authors.initials: A
authors.lastname: Leroux
authors.forename: Pascal
authors.initials: P
authors.lastname: Genin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000943:Antigens, Differentiation / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D002277:Carcinoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology* / Q000556:secondary; D002454:Cell Differentiation; D048430:Cell Shape; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D018734:Genes, erbB-2; D006801:Humans; D008207:Lymphatic Metastasis; D008679:Metaplasia; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012509:Sarcoma / Q000473:pathology
chemical_list: D000943:Antigens, Differentiation; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone