title: Distribution of aldehyde dehydrogenase 1-positive stem cells in benign mammary tissue from women with and without breast cancer.
abstract: OBJECTIVE
  Aldehyde dehydrogenase 1 (ALDH1) in female breast tissue has been linked to stem cells, but little is known about the benign cellular organization in situ. We investigated the distribution of ALDH1-immunoreactive (ALDH1+) cells in histomorphologically benign breast tissue from 28 women with or without breast cancer.
  
  
  RESULTS
  ALDH1+ cells were detected in benign tissue of women aged 20-72 years, located most commonly at the luminal and intermediate ductular levels and in the stroma. ALDH1+ cell populations and Ki67+ cell populations were present in separate ductules, both cell types rarely showing epithelial differentiation. ALDH1+ cells were non-reactive to Ki67 and oestrogen receptor. Stromal round/oval ALDH1+ non-leukocyte cells in both age groups expressed contractile protein. There was a lower concentration of luminal and intermediate ductular ALDH1+ cells in postmenopausal women than in premenopausal women, and in cancer patients than in non-cancer patients, and a higher concentration in women receiving exogenous hormones.
  
  
  CONCLUSIONS
  This study provides further evidence for the stem cell character of ALDH1+ cells, here in benign breast tissue of cancer and non-cancer patients throughout non-lactating adult life, and contributes evidence of benign stromal ALDH1+ cells. The distribution of ductular ALDH1+ stem cells appears to be influenced by hormonal status.
authors.affiliation: Department of Pathology, Telemark Hospital, Skien, Norway. isfoss@mac.com
authors.forename: Björn L
authors.initials: BL
authors.lastname: Isfoss
authors.forename: Bo
authors.initials: B
authors.lastname: Holmqvist
authors.forename: Per
authors.initials: P
authors.lastname: Alm
authors.forename: Håkan
authors.initials: H
authors.lastname: Olsson
mesh_terms: D000328:Adult; D000368:Aged; D000080924:Aldehyde Dehydrogenase 1 Family; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D042361:Mammary Glands, Human / Q000201:enzymology* / Q000473:pathology; D008875:Middle Aged; D050697:Retinal Dehydrogenase / Q000378:metabolism*; D013234:Stem Cells / Q000201:enzymology*
chemical_list: D007527:Isoenzymes; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase