title: Co-expression of stem cell markers ALDH1 and CD44 in non-malignant and neoplastic lesions of the breast.
abstract: OBJECTIVE
  The Cancer Stem Cell (CSC) model proposes that cancer is driven by a cellular component which possesses stem cell (SC) properties, cancer stem cells (CSCs), a distinct cell-type which is tumorigenic and capable of invasion and metastasis. Enzymatic activity of aldehyde dehydrogenase-1 (ALDH1), a de-toxifying enzyme that oxidizes intracellular aldehydes, has been used as a marker of normal and malignant breast stem cells (BSCs). CD44-transmembrane protein has already been shown to possess the ability to identify breast epithelial cells with stem properties.
  
  
  METHODS
  In order to compare two of the currently most reliable BSCs markers, ALDH1 and CD44, and to correlate their expression within different breast lesions, 190 samples from breast cancer specimens were analyzed by tissue microarrays.
  
  
  RESULTS
  ALDH1 expression was observed in 85.43% and CD44 in 90.3% of all samples. No overexpression was observed for ALDH1 between invasive tumors, ductal carcinomas in situ and non-malignant lesions of breast, although ALDH1 had a significant negative correlation with estrogen-receptor (ER) and progesterone-receptor (PR) status (p=0.002 and p=0.001, respectively) and a positive correlation with CD44 (p<0.001). Moreover, combined overexpression of ALDH1 and CD44 was observed in ductal in situ tumors (p<0.001).
  
  
  CONCLUSIONS
  The combined overexpression of these markers in ductal carcinomas in situ is in agreement with the CSC model in breast cancer.
authors.affiliation: MSc. and Carlos Lopes, Department of Pathology and Molecular Immunogenetics, Institute of Biomedical Sciences Abel Salazar. Jorge Viterbo Ferreira Street, n° 288, 4050-313, Porto, Portugal. arnaudcpaula@hotmail.com, calopes@icbas.up.pt.
authors.forename: Arnaud
authors.initials: A
authors.lastname: DA Cruz Paula
authors.forename: Oriana
authors.initials: O
authors.lastname: Marques
authors.forename: Ana Margarida
authors.initials: AM
authors.lastname: Rosa
authors.forename: Maria
authors.initials: M
authors.lastname: DE Fátima Faria
authors.forename: Alexandra
authors.initials: A
authors.lastname: Rêma
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopes
mesh_terms: D000080924:Aldehyde Dehydrogenase 1 Family; D014408:Biomarkers, Tumor / Q000378:metabolism; D001940:Breast / Q000378:metabolism* / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D015331:Cohort Studies; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D007527:Isoenzymes / Q000378:metabolism*; D009367:Neoplasm Staging; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D011379:Prognosis; D050697:Retinal Dehydrogenase / Q000378:metabolism*; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; C497483:CD44 protein, human; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D018960:Hyaluronan Receptors; D007527:Isoenzymes; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase
keywords: ALDH1; Breast cancer; CD44; breast stem cells; cancer stem model