title: Cyclooxygenase-2 expression in canine appendicular osteosarcomas.
abstract: Osteosarcoma is the most common primary bone tumor in dogs and it has a high mortality rate from distant metastatic disease. Targeted adjuvant therapies are needed to prolong currently achievable survival times. The role of cyclooxygenase-2 (COX-2) in carcinogenesis has been attributed to the production of prostaglandins and involvement in apoptosis, immune surveillance, and angiogenesis. COX-2 is up-regulated in a number of different human and animal epithelial tumors, but data about its function in mesenchymal tumors is lacking. The purpose of this study was to evaluate COX-2 expression in canine appendicular osteosarcomas and to identify if a relationship exists between the intensity of COX-2 expression and clinicopathologic outcome. Of 44 osteosarcomas analyzed, 34 (77.3%) were positive for COX-2 expression. Most of the positive cases (88%) had poor to moderate COX-2 staining. Dogs that had strong COX-2 expression had significantly decreased overall survival time (P = .0107). The median survival times for dogs with negative (n = 10), poor (n = 19), moderate (n = 11), and strong (n = 4) expression were 423, 399, 370, and 86 days, respectively. Additional studies are warranted to further evaluate COX-2 in osteosarcoma for its prognostic value and as a target for adjuvant therapy.
authors.affiliation: Animal Cancer Center, Departments of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. mmullins@colostate.edu
authors.forename: Marie N
authors.initials: MN
authors.lastname: Mullins
authors.forename: Susan E
authors.initials: SE
authors.lastname: Lana
authors.forename: William S
authors.initials: WS
authors.lastname: Dernell
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Ogilvie
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Withrow
authors.forename: E J
authors.initials: EJ
authors.lastname: Ehrhart
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western / Q000662:veterinary; D001859:Bone Neoplasms / Q000378:metabolism / Q000662:veterinary*; D003120:Colorado / Q000453:epidemiology; D051546:Cyclooxygenase 2; D004283:Dog Diseases / Q000378:metabolism* / Q000401:mortality; D004285:Dogs; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D007150:Immunohistochemistry / Q000662:veterinary; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D012516:Osteosarcoma / Q000378:metabolism / Q000662:veterinary*; D011237:Predictive Value of Tests; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D016019:Survival Analysis
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases