title: Strong evidence for up-regulation of cyclooxygenase-1 in head and neck cancer.
abstract: BACKGROUND
  Cyclooxygenase-1, in contrast to cyclooxygenase-2, is generally reported to be constitutively expressed as a housekeeping enzyme in many different tissues. A number of recently published reports, however, challenge the notion that cyclooxygenase-1 expression is invariably constitutive by demonstrating that this enzyme might be up-regulated under certain pathological conditions in, for example, breast or ovarian cancer cells. In this study we investigated the expression of cyclooxygenase-1 in head and neck tumours and compared it to the cyclooxygenase-1 expression levels in normal oropharyngeal epithelial cells.
  
  
  METHODS
  Paraffin-embedded pretreatment biopsies were obtained from head and neck tumour patients (n = 35). In addition, samples of normal oropharyngeal mucosa were taken from patients (n = 12) undergoing routine tonsillectomy. Cyclooxygenase-1 expression levels were determined by immunohistochemistry, Western blotting and real-time RT-PCR in cancerous tissue versus normal mucosa.
  
  
  RESULTS
  Immunohistochemistry revealed overexpression of cyclooxygenase-1 in tumour biopsies compared to normal mucosa. Cyclooxygenase-1 was highly synthesized in the cytoplasm of neoplastic cells while significantly lower levels were detectable in normal mucosal cells. Western blotting and real-time RT-PCR also demonstrated higher cyclooxygenase-1 levels in tumour specimens compared to normal tissue samples.
  
  
  CONCLUSIONS
  In this study we show for the first time that cyclooxygenase-1 is overexpressed in head and neck cancer cells compared to epithelial cells of normal mucosa.
authors.affiliation: Department of Otorhinolaryngology, The Medical University of Vienna, Austria.
authors.forename: B M
authors.initials: BM
authors.lastname: Erovic
authors.forename: M
authors.initials: M
authors.lastname: Woegerbauer
authors.forename: J
authors.initials: J
authors.lastname: Pammer
authors.forename: E
authors.initials: E
authors.lastname: Selzer
authors.forename: M Ch
authors.initials: MCh
authors.lastname: Grasl
authors.forename: D
authors.initials: D
authors.lastname: Thurnher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000201:enzymology*; D051545:Cyclooxygenase 1 / Q000378:metabolism*; D004847:Epithelial Cells / Q000201:enzymology; D005260:Female; D006258:Head and Neck Neoplasms / Q000201:enzymology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009960:Oropharynx / Q000201:enzymology; D015854:Up-Regulation
chemical_list: D051545:Cyclooxygenase 1