Evaluation of immunohistopathological profile of tubular and solid canine mammary carcinomas.

Breast cancer is the most common cancer in women, but the incidence of mammary carcinoma in female dogs is even higher than in humans. These two tumors have similarities that can be seen by its biological behavior, molecular genetic alterations, and histology. This suggest that female dogs can be an excellent model for preclinical oncological studies. And the mammary carcinoma most frequently found in this species is the tubular and solid carcinomas. The extracellular matrix (ECM) has an important role in the progression of these tumors. Because of that we proposed to evaluate the ECM components of these carcinomas through histology with specific stains such as Masson's Trichrome, Picrosirius Red and the technique of scanning electron microscopy. With that, we found the presence of collagen fibers in the tubular carcinoma and around its parenchyma. On the other hand, the solid carcinoma presented collagen fibers throughout the parenchyma and around each tumor cell. With the transmission electron microscopy, we observed the presence of mitochondrias and rough endoplasmic reticulum in both tumors. And finally, we evaluated the expression of proteins through the immunohistochemistry, in which we found a high expression of VEGF, PCNA, CK-18 and vimentin in solid carcinoma, and a positive mark in the tubular and solid carcinoma for collagen I, III and fibronectin. Thus, we demonstrated some differences in the ECM of these mammary carcinomas, allowing a better understanding of its histological characteristics, and these data may contribute to future studies about therapies focused on tumors ECM.

Canine amniotic membrane mesenchymal stromal/stem cells: Isolation, characterization and differentiation.

The amniotic membrane can be considered as one of the sources of isolation of these cells, since it is found in the fetal maternal interface and has low immunogenicity. Mesenchymal stromal/stem cells (MSCs) have not been identified in canine amniotic membrane (AMC). Therefore, our objective was to isolate, culture, characterize and differentiate cells derived from canine amniotic membrane (AMC) and to verify its immunological and tumorigenic potential. For this, 12 dogs fetuses of each gestational age 32, 43 and 55 days were used, and the isolation and culture of the AMC were performed. We observed that the cells presented fibroblastoid morphology and high confluence even after freezing. We also observed that, when induced, they were able to differentiate into osteogenic, adipogenic, and chondrogenic cells, as well as being CD34- and CD105+. Regarding the immunological markers, we found that IL-1, IL-2, IL-6, IL-10 and MHC II were not expressed, whereas MHC I was expressed. After application of AMC cells in nude mice we can verify that there was no tumor formation. Based on this, we conclude that canine amniotic membrane is a good and accessible source for obtaining MSCs of low immunogenic and tumorigenic potential for veterinary therapeutic applications.