title: Loss of expression of the cancer stem cell marker aldehyde dehydrogenase 1 correlates with advanced-stage colorectal cancer.
abstract: BACKGROUND
  Colorectal cancer (CRC) progression is mediated by cancer stem cells (CSCs). We sought to determine if the expression of the CSC marker aldehyde dehydrogenase 1 (ALDH1) in CRC tumors varies by American Joint Committee on Cancer stage or correlates to clinical outcomes.
  
  
  METHODS
  Primary and metastatic CRC samples from 96 patients were immunostained with antibodies to ALDH1 and imaged to evaluate marker expression. The percentage of ALDH1(+) cells was correlated to clinical outcomes.
  
  
  RESULTS
  ALDH1 was overexpressed in CRC tumors compared with nonneoplastic tissue. Marker expression was highest in nonmetastatic tumors. The loss of expression was associated with advanced stage and metastatic disease. No significant correlation was found between ALDH1 expression and metastasis, recurrence, or survival.
  
  
  CONCLUSIONS
  ALDH1 was highly expressed in nonmetastatic CRC, but expression was lost with advancing stage. ALDH1 could be an effective therapeutic target in early CRC but not late-stage disease. No correlation was found between ALDH1 and disease prognosis.
authors.affiliation: Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, L223, Portland, OR 97239, USA. Electronic address: hessmanc@ohsu.edu.
authors.forename: Crystal J
authors.initials: CJ
authors.lastname: Hessman
authors.affiliation: Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, L223, Portland, OR 97239, USA.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Bubbers
authors.affiliation: Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, L223, Portland, OR 97239, USA; Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Billingsley
authors.affiliation: Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, L223, Portland, OR 97239, USA; Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Herzig
authors.affiliation: Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA; Department of Dermatology, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Melissa H
authors.initials: MH
authors.lastname: Wong
mesh_terms: D000080924:Aldehyde Dehydrogenase 1 Family; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000473:pathology*; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D009367:Neoplasm Staging; D014411:Neoplastic Stem Cells / Q000201:enzymology*; D050697:Retinal Dehydrogenase / Q000096:biosynthesis*
chemical_list: D007527:Isoenzymes; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase