title: Spatial distribution of cancer stem cells in head and neck squamous cell carcinomas.
abstract: BACKGROUND
  CD44 and aldehyde dehydrogenase 1 (ALDH1) are considered putative markers of highly tumorigenic cells (i.e., cancer stem-like cells) in head and neck squamous cell carcinomas. This small subset of cells is believed to be the primary responsible for tumor initiation and progression. The objectives of this study were (i) to evaluate the patterns of CD44 and ALDH1 expression in the tumor center and in the invasive front, as well as in adjacent non-tumor epithelium, and (ii) to correlate these findings with clinical parameters.
  
  
  METHODS
  The sample comprised 44 patients with primary head and neck squamous cell carcinomas. Hematoxylin and eosin (HE) staining was used for histopathological tumor grading and for morphological analysis of adjacent non-tumor epithelium. Semiquantitative analysis was performed in histological sections immunostained for CD44 and ALDH1.
  
  
  RESULTS
  ALDH1 immunostaining in the invasive front showed positive association with tumor size, regional metastasis, tumor histopathological grading, and disease progression. Moreover, expression of this marker in both tumor invasive front and adjacent non-tumor epithelium was related with more aggressive tumors. CD44 immunostaining was heterogeneous in all areas evaluated and did not show association with clinical data.
  
  
  CONCLUSIONS
  Collectively, these data suggest that ALDH1 immunostaining in the invasive front and in adjacent non-tumor epithelium may help identify tumors with a more aggressive behavior, potentially contributing to improving treatment customization and the monitoring of patients with head and neck cancer.
authors: Oral Pathology, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors: Laura C
authors: LC
authors: Hildebrand
authors: Ana L
authors: AL
authors: Carvalho
authors: Isabel S
authors: IS
authors: Lauxen
authors: Jacques E
authors: JE
authors: Nör
authors: Carlos T S
authors: CT
authors: Cerski
authors: Manoel
authors: M
authors: Sant'Ana Filho
mesh_terms: D000328:Adult; D000368:Aged; D000080924:Aldehyde Dehydrogenase 1 Family; D014408:Biomarkers, Tumor / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000556:secondary; D018450:Disease Progression; D018572:Disease-Free Survival; D004848:Epithelium / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis; D006965:Hyperplasia; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D014411:Neoplastic Stem Cells / Q000473:pathology*; D011230:Precancerous Conditions / Q000473:pathology; D050697:Retinal Dehydrogenase / Q000032:analysis; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; C497483:CD44 protein, human; D018960:Hyaluronan Receptors; D007527:Isoenzymes; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase
keywords: CD44; aldehyde dehydrogenase; head and neck squamous cell carcinomas; tumor-initiating cells; tumorigenesis