History In comparative pathology canine mammary tumours have special interest because of their similarities with human breast cancer. ex-pleomorphic adenomas and canine mixed tumour and metaplastic carcinoma) were evaluated. First clinical and morphologic aspects of benign and malignant variants were compared between the species. Then streptavidin-biotin-peroxidase immunohistochemistry was performed to detect the expression of cytokeratins vimentin p63 protein estrogen receptor β-catenin and E-cadherin. Results After standardization similar age and site distributions were observed in human and canine tumours. Histological similarities were identified in the comparison of the benign lesions as well. Metaplastic carcinomas also resembled general aspects of carcinomas ex-pleomorphic adenomas in morphological evaluation. Additionally immunohistochemical staining further presented similar antigenic expression between lesions. Conclusion There are many similar features between human salivary and canine mammary gland mixed tumours. This observation is of great relevance for those interested in the study and management of salivary gland tumours since canine lesions NSC 74859 may constitute useful comparative models for their investigations. Background Animal models have been widely used to NSC 74859 investigate several forms of human neoplasias. Because of centuries of coexistence with humans in the same environment dogs are of particular interest as they provide NSC NSC 74859 74859 important evolutionary information. In addition both species show great genotypic similarities . Thus spontaneous tumours of canine mammary glands have been proposed as comparative models for the study of human breast cancer since these lesions share epidemiological clinical behavioural and antigenic features [2-5]. Gleam well-known relationship between your incidence of human salivary and mammary glands tumours [6-9]. Morphological similarities have already been referred to between particular tumours of salivary glands and breasts neoplasias such as for example those existing between polymorphous low-grade adenocarcinoma and intrusive lobular carcinoma  between acinic cell carcinoma and intrusive secretory carcinoma  and between epithelial-myoepithelial carcinoma and adenomyoepithelioma . NSC 74859 SEL10 Ductal carcinomas [13 14 adenoid cystic carcinomas and combined tumours with identical patterns could be within both organs [15 16 Mixed tumours are uncommon lesions in the human being breast  however they are regular in both human being salivary and canine mammary glands [18-20]. Inside a comparative evaluation from the obtainable books pleomorphic adenoma (PA) and its own malignant counterpart the carcinomas ex-pleomorphic adenomas (Ca ex-PA) possess several interesting commonalities to harmless combined tumours (MT) also to metaplastic carcinomas (MC) of canine mammary glands. First all are produced from exocrine glands which depict identical tissue architecture. Up coming with few variants both are microscopically seen as a an assortment of ductal and myoepithelial components intermingling an evidently mesenchymal stroma of adjustable constitution [18-20]. Furthermore malignant transformation can be recognized for both for human being PA and canine MT especially in lesions with lengthy evolution and regular recurrences [20-25]. Regardless of these identical aspects to the very best of our understanding no particular comparative analysis between human being salivary and canine mammary glands tumours can be obtainable. Thus today’s work aimed to execute objective morphological microscopic comparison between mixed tumours derived from human salivary and canine mammary glands as well as to evaluate the immunohistochemical expression of some relevant antigens in order to characterize these two types of neoplastic alterations. Methods Samples Ten samples of PA and 10 of Ca ex-PA were obtained from the Department of Pathology of School of Medicine Federal University of Minas Gerais (UFMG Belo Horizonte Minas Gerais Brazil) A. C. Camargo Cancer Hospital (S?o Paulo S?o Paulo Brazil) and the National Cancer Institute (Rio de Janeiro Rio de Janeiro Brazil). Ten samples of MT and 10 of MC of mammary glands of dogs without defined breed were obtained from the records of the Laboratory of Comparative Pathology Biological Sciences Institute UFMG. Ca ex-PA diagnosis was restricted to cases with.