title: Evaluation of cyclooxygenase-2 expression in canine mast cell tumours.
abstract: Mast cell tumours (MCTs) are among the most common cutaneous neoplasms in dogs and have a highly variable clinical behaviour. Cyclooxygenase (Cox) catalyzes the rate-limiting step in prostanoid biosynthesis and has recently gained attention as a prognostic factor and therapeutic target in human and animal oncology. In order to evaluate the potential value of non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of canine MCTs, expression of Cox-2 was determined in 49 such tumours (14 of grade I, nine of grade II and 22 of grade III). Cox-2 was expressed by 86% of the tumours studied. The percentage of labelled cells ranged from isolated positive cells throughout the tumour (n=8) to localized foci of labelled cells (n=3) or diffuse labelling of >50% of the cells (n=31). The intensity of Cox-2 labelling ranged from weak (n=4) to moderate (n=16) and strong (n=22) and was greatest at the advancing margin of the tumour. The intensity of Cox-2 labelling was significantly different between the three histological groups (P=0.018). However, no significant differences were noted for the percentage of Cox-2 positive cells (P=0.122) and for the immunoreactivity score (P=0.348) between the histological grades. The results of this study suggest that NSAIDs, particularly Cox-2 inhibitors, may be of value in the treatment of canine MCTs.
authors.affiliation: CECAV, Department of Veterinary Sciences, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal.
authors.forename: Justina
authors.initials: J
authors.lastname: Prada
authors.forename: Felisbina Luisa
authors.initials: FL
authors.lastname: Queiroga
authors.forename: Hugo
authors.initials: H
authors.lastname: Gregório
authors.forename: Isabel
authors.initials: I
authors.lastname: Pires
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D052246:Cyclooxygenase 2 Inhibitors / Q000627:therapeutic use; D004283:Dog Diseases / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology; D004285:Dogs; D007124:Immunoenzyme Techniques / Q000662:veterinary; D008407:Mast Cells / Q000201:enzymology / Q000473:pathology*; D054705:Mastocytoma, Skin / Q000201:enzymology / Q000662:veterinary*; D012878:Skin Neoplasms / Q000201:enzymology / Q000662:veterinary*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000970:Antineoplastic Agents; D052246:Cyclooxygenase 2 Inhibitors; D051546:Cyclooxygenase 2