title: Telomerase activity is upregulated in laryngeal squamous cell carcinoma.
abstract: OBJECTIVE
  The immortalizing enzyme telomerase has been linked to carcinogenesis and is being targeted as a novel molecular marker. This study investigated telomerase expression in patients with laryngeal squamous cell carcinoma and correlated telomerase activity with conventional prognostic parameters.
  
  
  METHODS
  A consecutive series of patients with laryngeal squamous cell carcinoma undergoing surgical salvage for persistent or progressive disease after failed radiation therapy.
  
  
  METHODS
  Twenty patient samples of laryngeal squamous cell carcinoma and 20 adjacent histologically normal mucosal samples were assayed using the telomeric repeat amplification protocol (TRAP) method for detection of telomerase activity. The leukemic cell line, K562, acted as a positive control and the human fibroblast line, Hs21Fs, as a negative control. A sample was classified as telomerase positive when an RNase-sensitive hexameric repeat ladder was observed. Absence of laddering was considered a negative result.
  
  
  RESULTS
  Seventeen of 20 (85%) tumor samples and 4 of 20 (20%) adjacent histologically normal samples were telomerase positive. No statistically significant difference was observed when densitometric readings were compared by T category, tumor grade, or site (by ANOVA).
  
  
  CONCLUSIONS
  Although telomerase activity is present in laryngeal cancer, levels of activation do not correlate with conventional parameters used for prognostication. Our study indicates that the marker may be a useful adjunctive method in the diagnosis of malignancy after radiation failure.
authors.affiliation: Department of Otolaryngology, The Toronto Hospital/Princess Margaret Hospital, Ontario, Canada.
authors.forename: A J
authors.initials: AJ
authors.lastname: Curran
authors.forename: P J
authors.initials: PJ
authors.lastname: Gullane
authors.forename: J
authors.initials: J
authors.lastname: Irish
authors.forename: C
authors.initials: C
authors.lastname: Macmillan
authors.forename: J
authors.initials: J
authors.lastname: Freeman
authors.forename: S
authors.initials: S
authors.lastname: Kamel-Reid
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000235:genetics; D002460:Cell Line; D003720:Densitometry; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D005500:Follow-Up Studies; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D006801:Humans; D007820:Laryngeal Mucosa / Q000201:enzymology; D007822:Laryngeal Neoplasms / Q000201:enzymology* / Q000235:genetics; D007938:Leukemia / Q000201:enzymology / Q000235:genetics; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012260:Ribonucleases / Q000235:genetics; D019098:Telomerase / Q000235:genetics*; D017211:Treatment Failure; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D019098:Telomerase; D012260:Ribonucleases