title: Expression of aldehyde dehydrogenase 1 (ALDH1) is associated with basal-like markers and features of aggressive tumours in African breast cancer.
abstract: BACKGROUND
  Putative breast cancer stem cells might express surface markers such as aldehyde dehydrogenase 1 (ALDH1) and BMI-1 proteins. The aim of this study was to explore the expression of these proteins in breast cancers from an African population and their associations with the basal-like phenotype (BLP) and other molecular characteristics.
  
  
  METHODS
  We analysed 192 paraffin-embedded breast carcinoma samples by tissue microarrays and immunohistochemical methods.
  
  
  RESULTS
  In total, 88 tumours (48%) expressed ALDH1, whereas 46 (25%) expressed BMI-1 protein. Expression of ALDH1 was associated with high histological grade (P<0.0005), high mitotic count (P<0.0005), high nuclear grade (P<0.0005), oestrogen receptor (ER) negativity (P<0.0005), progesterone receptor (PR) negativity (P=0.009), p53 expression (P=0.034), cytokeratin 5/6 positivity (P=0.008), epidermal growth factor receptor (EGFR) expression (P=0.015) and the BLP (P<0.0005), whereas it was inversely associated with BMI-1 staining (P=0.009). On the other hand, BMI-1 expression was associated with low histological grade (P=0.004) and ER positivity (P=0.001).
  
  
  CONCLUSIONS
  There was a high prevalence of ALDH1 expression among breast carcinomas and associations with basal markers and features of aggressive tumours. Studies are required to elucidate the importance of these findings for improved understanding of breast cancer biology.
authors.affiliation: Section for Pathology, The Gade Institute, University of Bergen, Haukeland University Hospital, N-5021, Bergen, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Nalwoga
authors.forename: J B
authors.initials: JB
authors.lastname: Arnes
authors.forename: H
authors.initials: H
authors.lastname: Wabinga
authors.forename: L A
authors.initials: LA
authors.lastname: Akslen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000444:Aldehyde Dehydrogenase / Q000096:biosynthesis*; D000080924:Aldehyde Dehydrogenase 1 Family; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D044383:Black People / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis; D010641:Phenotype; D063150:Polycomb Repressive Complex 1; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D012097:Repressor Proteins / Q000096:biosynthesis; D050697:Retinal Dehydrogenase; D046888:Tissue Array Analysis; D014454:Uganda; D055815:Young Adult
chemical_list: C069077:BMI1 protein, human; D014408:Biomarkers, Tumor; D007527:Isoenzymes; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D000080924:Aldehyde Dehydrogenase 1 Family; D000444:Aldehyde Dehydrogenase; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase; D063150:Polycomb Repressive Complex 1