title: Impact of telomerase status on canine osteosarcoma patients.
abstract: BACKGROUND
  We demonstrated previously that canine osteosarcoma (OSA) cell lines and samples from clinical patients are predominantly telomerase positive. In contrast, the majority of OSA samples from human patients appear to be telomerase negative, maintaining telomere length by an alternative lengthening of telomeres (ALT) mechanism. The purpose of the current study was to examine the telomerase status of a large number of OSA samples from dogs and determine if telomerase status can serve as a prognostic factor.
  
  
  OBJECTIVE
  The majority of clinical canine OSA appendicular lesions will be telomerase positive, and telomerase positivity will negatively impact disease outcome.
  
  
  METHODS
  Sixty-seven dogs with appendicular OSA presenting to the Colorado State University Animal Cancer Center for treatment.
  
  
  METHODS
  The Telomeric Repeat Amplification Protocol was performed on tissue samples from primary canine appendicular OSA to determine the presence of telomerase activity. Telomere restriction fragment (TRF) analysis was utilized to determine telomere length and detect ALT. Outcome data were obtained in a retrospective manner and correlated with telomerase status.
  
  
  RESULTS
  Seventy-three percent of canine OSA samples were telomerase positive. Telomerase status did not have an impact on disease-free interval or survival time. Nine of 10 telomerase-negative samples examined were consistent with an ALT phenotype, based on TRF analysis.
  
  
  CONCLUSIONS
  These results are consistent with the hypothesis that the majority of canine OSA are telomerase positive, suggesting that telomerase may be a valuable target for canine OSA therapy. Additionally, telomerase status does not appear to be a prognostic factor in canine OSA.
authors.affiliation: Department of Clinical Science, Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. kelvin.kow@oregonstate.edu
authors.forename: K
authors.initials: K
authors.lastname: Kow
authors.forename: D H
authors.initials: DH
authors.lastname: Thamm
authors.forename: J
authors.initials: J
authors.lastname: Terry
authors.forename: K
authors.initials: K
authors.lastname: Grunerud
authors.forename: S M
authors.initials: SM
authors.lastname: Bailey
authors.forename: S J
authors.initials: SJ
authors.lastname: Withrow
authors.forename: S E
authors.initials: SE
authors.lastname: Lana