title: Stem cell growth factor receptor in canine vs. feline osteosarcomas.
abstract: Osteosarcoma is considered the most common bone cancer in cats and dogs, with cats having a much better prognosis than dogs, since the great majority of dogs with osteosarcoma develop distant metastases. In search of a factor possibly contributing to this disparity, the stem cell growth factor receptor KIT was targeted, and the messenger (m)RNA and protein expression levels of KIT were compared in canine vs. feline osteosarcomas, as well as in normal bone. The mRNA expression ofKITwas quantified by reverse transcription-quantitative polymerase chain reaction, and was observed to be significantly higher in canine (n=14) than in feline (n=5) osteosarcoma samples (P<0.001). KIT protein expression was evaluated by immunohistochemistry, which revealed that 21% of canine osteosarcoma samples did not exhibit KIT staining in their neoplastic cells, while in 14% of samples, a score of 1 (<10% positive tumour cells) was observed, and in 50% and 14% of samples, a score of 2 (10-50% positivity) and 3 (>50% positivity), respectively, was observed. By contrast, the cancer cells of all the feline bone tumour samples analysed were entirely negative for KIT. Notably, canine and feline osteocytes of healthy bone tissue lacked any KIT expression. These results could be the first evidence that KIT may be involved in the higher aggressiveness of canine osteosarcoma compared with feline osteosarcoma.
authors.affiliation: Department of Companion Animals and Horses, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Birgitt
authors.initials: B
authors.lastname: Wolfesberger
authors.affiliation: Department of Pathobiology, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Andrea
authors.initials: A
authors.lastname: Fuchs-Baumgartinger
authors.affiliation: Department of Pathobiology, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Juraj
authors.initials: J
authors.lastname: Hlavaty
authors.affiliation: Department of Pathobiology, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Florian R
authors.initials: FR
authors.lastname: Meyer
authors.affiliation: Genomics Core Facility, VetCore, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Hofer
authors.affiliation: Genomics Core Facility, VetCore, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Ralf
authors.initials: R
authors.lastname: Steinborn
authors.affiliation: Department of Pathobiology, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Christiane
authors.initials: C
authors.lastname: Gebhard
authors.affiliation: Department of Pathobiology, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Walter
keywords: KIT; RT-qPCR; bone tumour; cat; dog; immunohistochemistry