title: Telomerase expression in uveal melanoma.
abstract: OBJECTIVE
  Accumulating evidence indicates that telomerase activity is repressed in normal human somatic cells but reactivated in cancers and immortal cells, suggesting that activation of telomerase activity has a role in carcinogenesis and immortalisation. To date, telomerase in uveal melanoma and, whether, it may have a role in the development or progression of these tumours has not been described. The expression patterns and the activity of telomerase were investigated in 14 uveal melanoma and these results were correlated with histological and immunohistological features of these tumours.
  
  
  METHODS
  A modified PCR based telomeric repeat amplification protocol (TRAP) assay was used to demonstrate telomerase activity in 14 uveal melanomas. In addition, in situ hybridisation was used to demonstrate the expression pattern of the telomerase RNA component (hTR) at the single cell level in eight of these globes.
  
  
  RESULTS
  The TRAP assay revealed moderate telomerase activity in all uveal melanomas examined. In situ hybridisation visualised a moderate to high upregulation of hTR in the melanoma cells but not in the admixed reactive cells. There was no correlation among tumour location, cell type, or growth fraction and the amount of telomerase activity. In addition, the cells of the germinative zone of the lens demonstrated a strong hTR expression.
  
  
  CONCLUSIONS
  Telomerase activity is upregulated in uveal melanomas. The expression of hTR was located to the tumour cells and not the reactive tumour infiltrating cells. Strong telomerase expression was also demonstrated in cells of the germinative zone of the lens.
authors.affiliation: Department of Pathology, University Hospital Benjamin Franklin, Free University, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Heine
authors.forename: S E
authors.initials: SE
authors.lastname: Coupland
authors.forename: S
authors.initials: S
authors.lastname: Kneiff
authors.forename: G
authors.initials: G
authors.lastname: Demel
authors.forename: N
authors.initials: N
authors.lastname: Bornfeld
authors.forename: M
authors.initials: M
authors.lastname: Hummel
authors.forename: H
authors.initials: H
authors.lastname: Stein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D016133:Polymerase Chain Reaction / Q000379:methods; D019098:Telomerase / Q000032:analysis* / Q000235:genetics; D014604:Uveal Neoplasms / Q000201:enzymology* / Q000235:genetics
chemical_list: D009363:Neoplasm Proteins; D019098:Telomerase