title: Cyclooxygenase-2 expression in canine mammary tumors.
abstract: Mammary tumors are the most common neoplasms in female dogs. Induction of cyclooxygenase-2 (COX-2) has been implicated in various cancers in humans. However, expression of COX-2 has not been investigated in canine mammary tumors. Normal mammary gland (n = 4), simple or complex adenomas (n = 63), and simple or complex adenocarcinomas (n = 84) were studied by immunohistochemistry. Results showed that COX-2 was not expressed in the normal gland but was detected in 24% of adenomas and in 56% of adenocarcinomas (P < 0.001). The incidence of COX-2 expression and the intensity of the COX-2 signal were higher in adenocarcinomas than in adenomas (P < 0.001). These results demonstrate for the first time that COX-2 is induced in a proportion of canine mammary tumors and that COX-2 expression is more frequent and more intense in malignant than in benign tumors, suggesting a potential role for COX-2 in canine mammary tumorigenesis.
authors.affiliation: Département de pathologie et microbiologie, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada J2S 7C6. doremo@medvet.umontreal.ca.
authors.forename: M
authors.initials: M
authors.lastname: Doré
authors.forename: I
authors.initials: I
authors.lastname: Lanthier
authors.forename: J
authors.initials: J
authors.lastname: Sirois
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000473:pathology / Q000662:veterinary*; D000236:Adenoma / Q000201:enzymology / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D051546:Cyclooxygenase 2; D004283:Dog Diseases / Q000201:enzymology* / Q000473:pathology; D004285:Dogs; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D007527:Isoenzymes / Q000096:biosynthesis*; D015674:Mammary Neoplasms, Animal / Q000201:enzymology* / Q000473:pathology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*
chemical_list: D007527:Isoenzymes; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases