title: Immunoprofile of metaplastic carcinomas of the breast.
abstract: OBJECTIVE
  Metaplastic breast carcinoma (MBC) is a rare type of breast cancer; its diagnosis in routine practice can be challenging, and may require immunohistochemical (IHC) characterization if no conventional invasive or in-situ carcinoma is present. Previous IHC studies of MBC often had a small sample size and did not investigate the different histological subtypes. This study aimed to assess the immunoprofile of MBC subtypes in a large series.
  
  
  RESULTS
  A total of 172 MBC diagnosed in routine and referral practice in Nottingham during 26 years were reviewed by three breast pathologists. In addition, data on the immunoprofile of 730 MBC in 61 published studies were analysed. The antibodies to a broad spectrum of cytokeratins (AE1/AE3 and MNF116) are most frequently positive in MBC (approximately 80%). Basal cytokeratins (34βE12, CK5/6, CK14 and CK17) are positive in approximately 70%. Luminal cytokeratins (CK8/18, CK7 and CK19) are positive in approximately 30-60%. Myoepithelial markers are also frequently positive, particularly p63. Oestrogen receptor (ER), progestogen receptor (PR) and HER2 are usually all negative. CD34 (a marker often positive in phyllodes tumours) is consistently negative in MBC.
  
  
  CONCLUSIONS
  This study provides data on the frequency of expression of a wide range of markers in MBC based on a large number of tumours. No consistent immunophenotype was identified and no individual marker was positive in all tumours, most probably reflecting the morphological and molecular heterogeneity of this tumour class and the practical need to use a panel of different antibodies when trying to establish the diagnosis of metaplastic breast carcinoma.
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham City Hospital, Nottingham, UK.|Department of Pathology, Faculty of Medicine, Menoufyia University, Menoufyia, Egypt.
authors.forename: Emad A
authors.identifier: http://orcid.org/0000-0002-5009-5525
authors.initials: EA
authors.lastname: Rakha
authors.affiliation: Department of Pathology, Instituto Português de Oncologia do Porto FG, Porto, Portugal.
authors.forename: Nuno D M
authors.identifier: http://orcid.org/0000-0002-7809-6597
authors.initials: ND
authors.lastname: Coimbra
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham City Hospital, Nottingham, UK.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Hodi
authors.affiliation: Department of Pathology, Jeddah, Saudi Arabia.
authors.forename: Enaam
authors.initials: E
authors.lastname: Juneinah
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham City Hospital, Nottingham, UK.
authors.forename: Ian O
authors.initials: IO
authors.lastname: Ellis
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham City Hospital, Nottingham, UK.
authors.forename: Andrew H S
authors.initials: AH
authors.lastname: Lee
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry
chemical_list: D014408:Biomarkers, Tumor
keywords: expression; immunohistochemistry; metaplastic breast carcinoma; profile; subtype