Search

The aim of our study was to investigate histopathologically the incidence of gastrointestinal tract tumours in dogs in the Czech Republic in relation to their age, sex and breed. In total, 29 gastric and 45 intestinal tumours from 3827 gastrointestinal tract biopsies were investigated. The average age of dogs with gastric lymphoma, adenocarcinoma, and other mesenchymal tumours was 7.3 years, 9.5 years, and > 10 years, respectively. Breed predisposition to adenocarcinoma was evidenced in the Belgian Shepherd and Leonberger, to lymphoma in the Doberman (P < 0.01). The most frequent site of adenocarcinoma was antrum pyloricum (66.7%); lymphomas involved gastric wall diffusely. The average age of dogs with intestinal adenoma, adenocarcinoma, lymphoma, leiomyoma or leiomyosarcoma and carcinoid was 7.5, 8.5, 8.5, 12, and 14 years, respectively. The age predisposition to intestinal adenoma and lymphoma was 7-8 years (P < 0.01) and to adenocarcinoma 7-8 years (P < 0.05); mesenchymal tumours occurred at the age of 11-12 years (P < 0.01). Breed predisposition to intestinal adenoma was evidenced in the Pug, Leonberger and English Setter (P < 0.01), to adenocarcinoma in the English Setter (P < 0.01) and Hovawart (P < 0.05), to lymphoma in the Doberman and Hovawart (P < 0.05). The most frequent site of occurrence of intestinal tumours was the colorectal region. The study revealing breed, sex and age predisposition to gastrointestinal tumours in dogs has not been described yet in the literature. [ABSTRACT FROM AUTHOR]

Simple Summary: The expression patterns of selected Wnt pathway molecules were analyzed in two of the most common canine oral neoplasia—canine oral squamous cell carcinoma (COSCC) and canine acanthomatous ameloblastoma (CAA). We found an overlap of areas with high expression of FZD6 and SOX2 in COSCC, while cytokeratin expression was low in these areas, indicating the low differentiation status of these cells. In CAA, FZD6-positive areas expressed cytokeratin and exhibited features of squamous metaplasia. Moreover, the expression of β-catenin and AXIN2 was higher in both CAA and COSCC than in the healthy canine oral epithelium. This work uncovered the distinct expression patterns of Wnt molecules in both lesions, indicating the involvement of this pathway in the pathology of canine oral cancers, which presents opportunities for their usage for the prediction of cell behavior or in the development of new therapeutic approaches. The Wnt signaling pathway is well known to be involved in many types of human cancer; however, in veterinary medicine, the investigation of individual Wnt members' expression, and their role in or association with oral tumor pathogenesis, is still underevaluated. We aim to determine the expression pattern of Frizzled-6 (FZD6) as one of the Wnt receptors in two of the most common canine oral neoplastic lesions—canine oral squamous cell carcinoma (COSCC) and canine acanthomatous ameloblastoma (CAA). While COSCC is a malignant tumor with aggressive biological behavior and a tendency to metastasize, CAA is a benign tumor with high local invasiveness. In CAA, the expression of FZD6 was mostly located in the center of the epithelial tumorous tissue, and cells exhibiting features of squamous metaplasia were strongly positive. In well-differentiated COSCC, FZD6 was expressed in the tumorous epithelium as well as the tumorous stroma. There was a negative correlation between cytokeratin expression and FZD6 expression in COSCC, where the central parts of the epithelial tumorous tissue were often FZD6-negative. The non-differentiated COSCC with low expression of cytokeratin exhibited a diffuse FZD6 signal. The invasive front with areas of tumor budding exhibited high FZD6 expression with a loss of cytokeratin expression. Moreover, the expression of β-catenin and AXIN2 was increased in comparison to gingiva. In conclusion, our study revealed significant differences in the expression patterns and the levels of FZD6 between COSCC and CAA, indicating the differential engagement of the Wnt pathway in these tumors. [ABSTRACT FROM AUTHOR]

Many types of tumorous and tumour-like lesions occur in the oral cavity of dogs. Even benign neoplasia often represents great inconvenience due to potential restrictions of therapeutic surgical approach in this area. Whereas in human medicine, there are statistical data describing areas of the oral cavity, that are more prevalent for development of particular neoplasia, in veterinary medicine, these data are not yet available. The aim of this study was to evaluate the prevalence of tumours in dogs with oral neoplasia, the occurrence site of the most common neoplastic lesions in the canine oral cavity, as well as the effect of age and sex on the prevalence of these lesions. In this study we investigated oral tumorous lesions from 659 dogs, out of which 352 lesions were diagnosed as tumours and 307 as tumour-like lesions. The most common tumours encountered were melanoma (42%, n = 148), squamous cell carcinoma (16%, n = 57) and canine acanthomatous ameloblastoma (10%, n = 35). The median age of dogs with oral neoplasia was 9.9 years, with the range of 0.2 to 17.5 years. There was no significant association between sex and the type of oral lesion (tumorous and tumour-like). Melanoma was most commonly present in the caudal maxillary region, squamous cell carcinoma on the mouth floor, canine acanthomatous ameloblastoma in the area of the rostral mandible, plasmacytoma on the tongue, osteosarcoma was most often diagnosed in the caudal parts of oral cavity and fibrosarcoma did not have a specific site of occurrence. [ABSTRACT FROM AUTHOR]