title: Aldehyde dehydrogenase isoform 1 (ALDH1) expression as a predictor of radiosensitivity in laryngeal cancer.
abstract: BACKGROUND
  Aldehyde dehydrogenase isoform 1 (ALDH1) has been shown to be a marker of cancer stem cells (CSCs). These stem cells may be responsible for tumour perpetuation as well as local and distant invasion. Several studies have shown that CSCs are more chemoradiotherapy (CRT)-resistant and may be responsible for tumour recurrence. Other studies, in contrast, have found ALDH1 expression to be indicative of a better prognosis.
  
  
  METHODS
  We retrospectively evaluated 84 patients diagnosed and treated for laryngeal cancer between 2006 and 2011. All patients underwent curative-intent radiotherapy or CRT at our institution. 57 of the 84 tumour samples contained sufficient material for ALDH1 assessment.
  
  
  RESULTS
  ALDH1 expression was detected in 17.5 % (10/57) of the tissue samples. None of the tumours from stage I patients tested positive for ALDH1. The relapse rate in ALDH1 + patients was 10 versus 51.2 % for ALDH1-. No differences in overall survival were observed between the groups; however, disease-free survival was 90 % for the ALDH1 + group versus 48.9 % for ALDH1- patients (p = 0.034).
  
  
  CONCLUSIONS
  The patients in this study with ALDH1 + tumours had better outcomes than their counterparts with ALDH1- tumours. This finding suggests that not all CSCs are resistant to conventional cancer treatments. It may also imply that new methods of correctly identifying these cells are needed.
authors.affiliation: Department of Radiation Oncology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain. margamm@yahoo.com.
authors.forename: M
authors.initials: M
authors.lastname: Martín
authors.affiliation: Department of Otorhinolaryngology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Hinojar
authors.affiliation: Department of Radiation Oncology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Cerezo
authors.affiliation: Department of Otorhinolaryngology, Hospital Universitario Infanta Sofía, Paseo de Europa, 34, San Sebastián de Los Reyes, 28702, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: García
authors.affiliation: Department of Radiation Oncology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Lopez
authors.affiliation: Department of Otorhinolaryngology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Prada
authors.affiliation: Department of Radiation Oncology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Marín
authors.affiliation: Department of Pathology, Instituto de Investigación Hospital de La Princesa, Diego de León 62, 28006, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Gamallo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000080924:Aldehyde Dehydrogenase 1 Family; D014408:Biomarkers, Tumor / Q000032:analysis*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000032:analysis / Q000096:biosynthesis*; D053208:Kaplan-Meier Estimate; D007822:Laryngeal Neoplasms / Q000201:enzymology / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000201:enzymology / Q000401:mortality / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000201:enzymology / Q000473:pathology; D011379:Prognosis; D016016:Proportional Hazards Models; D011836:Radiation Tolerance / Q000502:physiology*; D050697:Retinal Dehydrogenase / Q000032:analysis / Q000096:biosynthesis*; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor; D007527:Isoenzymes; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase
keywords: Aldehyde dehydrogenase; Cancer stem cells; Larynx carcinoma; Radiotherapy