title: Cancer stem cells markers CD44, CD24 and ALDH1 in breast cancer special histological types.
abstract: OBJECTIVE
  CD44, CD24 and ALDH1 are the most consistently used biomarkers to identify and characterise the breast cancer stem cell (CSC) phenotype. However, most studies performed until now analysed samples of invasive ductal carcinomas of no special type (IDC-NST). Therefore, prevalence and clinical significance of these CSC markers in breast carcinomas of special histological types (SHT) is largely unknown. For that reason, this study aims to determine the distribution of the breast CD44, CD24 and ALDH1 CSC markers among a series of invasive breast carcinomas of SHT, in comparison with a series of IDC-NST.
  
  
  METHODS
  117 invasive SHT breast carcinomas were analysed for the expression of CD44, CD24 and ALDH1, by immuhohistochemistry. The distribution of these CSC markers was evaluated among the distinct histological special types, and the results were compared with a series of 466 IDC-NST.
  
  
  RESULTS
  The expression prevalence of the breast CSC markers differed between special types and IDC-NST. Medullary, papillary and tubular carcinomas were enriched in the CSC phenotype CD44(+)/CD24(-/low) (80.0%, 100.0% and 100.0%, respectively, vs 45.3% in IDC-NST). Considering the ALDH1 cytoplasmic tumour expression, only medullary and metaplastic carcinomas displayed significant increase in CD44(+)/CD24(-/low)/ALDH1(+) CSC phenotype frequency (36.4% and 28.6%, respectively, vs 4.8% in IDC-NST).
  
  
  CONCLUSIONS
  The expression distribution of breast CSC markers is largely dependent on histological type. Interestingly, within the distinct SHT, medullary and metaplastic carcinomas are the two types highly associated with high-grade carcinomas, basal-like and claudin-low molecular subtypes, and to the CSC phenotype CD44(+)/CD24(-/low)/ALDH1(+).
authors.affiliation: IPATIMUP-Institute of Molecular Pathology and Immunology of Porto University, Porto, Portugal.
authors.forename: Francisco Ferro
authors.initials: FF
authors.lastname: de Beça
authors.forename: Pedro
authors.initials: P
authors.lastname: Caetano
authors.forename: Renê
authors.initials: R
authors.lastname: Gerhard
authors.forename: Cesar Augusto
authors.initials: CA
authors.lastname: Alvarenga
authors.forename: Madalena
authors.initials: M
authors.lastname: Gomes
authors.forename: Joana
authors.initials: J
authors.lastname: Paredes
authors.forename: Fernando
authors.initials: F
authors.lastname: Schmitt
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000080924:Aldehyde Dehydrogenase 1 Family; D014408:Biomarkers, Tumor / Q000378:metabolism; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D051927:CD24 Antigen / Q000378:metabolism*; D018276:Carcinoma, Medullary / Q000378:metabolism / Q000473:pathology; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D007527:Isoenzymes / Q000378:metabolism*; D008679:Metaplasia / Q000378:metabolism / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D050697:Retinal Dehydrogenase / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D051927:CD24 Antigen; C497889:CD24 protein, human; C497483:CD44 protein, human; D018960:Hyaluronan Receptors; D007527:Isoenzymes; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase