The aim of this paper is to discuss and update criteria that can guide the diagnosis, prognosis and treatment of canine and feline mammary neoplasms. It was elaborated during the IV Mammary Pathology Meeting: Diagnosis, Prognosis and Treatment of the Canine and Feline Mammary Neoplasia, held on April 29th and 30th, 2019 in Belo Horizonte – MG, Brazil, sponsored by the Laboratory of Comparative Pathology of the Federal University of Minas Gerais (UFMG), with the support of the Brazilian Association of Veterinary Pathology (ABPV) and Brazilian Association of Veterinary Oncology (ABROVET). Academics from several regions of Brazil were present and contributed to this work.

Mammary neoplasms are described as the third most common type of feline tumor, after haematopoietic and skin tumors, and present a challenge for clinicians because the prognosis for feline mammary tumors ranges from guarded to poor. Thus, it is necessary to define new therapeutic approaches and establish more in-depth knowledge about this disease in felines. The main aspects of the diagnosis, prognosis and treatment of feline mammary neoplasia were discussed, aiming to standardize the criteria and to serve as a guide for pathologists and veterinary clinicians.

STING (stimulator of interferon genes) is a cytosolic sensor for cyclic dinucleotides and also an adaptor molecule for intracellular DNA receptors. Although STING has important functions in the host defense against pathogens and in autoimmune diseases, its physiological relevance in intestinal homeostasis is largely unknown. In this study, we show that STING mice presented defective protective mechanisms of intestinal mucosa, including decreased number of goblet cells, diminished mucus production, and lower levels of secretory IgA, when compared with wild-type (WT) mice. Fecal content and microbiota DNA could activate STING, indicating a role of this molecule in gut. Microbiota composition was altered in STING mice toward a more inflammatory profile, evidencing a reduction in the Allobacolum and Bifidobacterium groups along with increase in Disulfovibrio bacteria. Absence of STING lead to decrease in induced intraepithelial lymphocytes (IEL) and to increase in group 1 innate lymphoid cell (ILC1) as well as ILC3 frequencies and decrease in ILC2 in the colon. Development and function of Foxp3+ and LAP+ regulatory T cells were also compromised in STING mice. Moreover, these mice were highly susceptible to dextran sodium sulfate-induced colitis, T-cell-induced colitis, and enteric Salmonella typhimurium infection when compared with WT animals. Therefore, our results identify an important role of STING in maintaining gut homeostasis and also a protective effect in controlling gut inflammation.

Mammary neoplasms are the most frequent tumors in female dogs. Of these neoplasms, benign mixed tumors (BMTs) and carcinomas in mixed tumors (CMTs) represent a large proportion of small animal oncology diagnoses. Together with carcinosarcomas (CSs), these three neoplastic entities are characterized by the proliferation of benign or malignant epithelial, myoepithelial, and mesenchymal cells, depending on their histological types. This histological heterogeneity, in addition to their molecular heterogeneity, confers these tumors with distinct biological behavior, which results in the need for different clinical and therapeutic approaches. The present consensual document elucidates the oncological issues related to the diagnosis, prognosis, and treatment of BMTs, CMTs, and CSs of the canine mammary gland.

Background: Presence of tumor markers in serum might be connected to the number of secreting cells and with the stage of the neoplasm. However, there are few studies regarding these markers in veterinary clinical oncology.Objectives: To determine the serum concentrations of cancer antigen 15.3 (CA 15.3), carcinoembryonic antigen (CEA), and lactate dehydrogenase (LDH) in female dogs with different stages of mammary cancer.Animals: Ninety female dogs, including 30 that were healthy, 40 that had nonmetastatic cancer, 12 with regional metastasis, and 8 with distant lymph node metastasis.Methods: Prospective case-controlled observational study. Serum samples were collected to measure CA15.3, CEA, and LDH from 60 female dogs with mammary cancer during mastectomy and 30 healthy female dogs during routine check-up. CA15.3 and CEA were determined by chemiluminescent immunoassay and LDH by ultraviolet kinetic method. Western blotting analysis was performed to confirm the specificity and possible cross-reactivity of human CA15.3 and CEA antibodies with canine serum. Group data were compared by ANOVA followed by Student-Newman-Keuls and Tukey's tests. Correlations were investigated by Pearson and Spearman tests.Results: CEA, CA15.3, and LDH were measurable in all groups. Higher serum concentration of CA15.3 and LDH was associated with regional and distant metastases. There was a significantly higher serum CA15.3 concentration in animals with lymph node metastasis when compared with animals without metastasis. There were no significant differences in CEA among groups. Expression of CA15.3 and CEA in canine serum was confirmed by Western blotting.Conclusions and Clinical Importance: Serum CA15.3 can be used to distinguish nonmetastatic from metastatic carcinomas.