The relations between GATA-3 and SOX-10 expressions, molecular subtypes, histopatological diagnosis and grades of epithelial canine mammary tumors

In this study, the immunohistochemical expression of GATA-3 and SOX-10 in canine mammary tumors was evaluated, and their relationships with tumor histopathological subtype, tumor grade, molecular subtype, and survival time were investigated. In this retrospectively designed study, paraffin-embedded tissue sections from 100 canine mammary tumor samples were prepared for immunohistochemical analysis. The indirect immunoperoxidase method was applied to detect the expression of GATA-3 and SOX-10 proteins. In addition, estrogen receptor, progesterone receptor, Her-2, and p63 antibodies were used to determine the molecular subtype of each tumor. Sections were deparaffinized, rehydrated, and subjected to antigen retrieval prior to incubation with primary antibodies. Following the application of secondary antibodies and chromogen development, the slides were counterstained with hematoxylin and evaluated under a light microscope. Histopathological examination revealed that the most common tumor types were tubular carcinoma (27%), complex carcinoma (19%), and tubulopapillary carcinoma (12%). According to tumor grade distribution, 46% of cases were classified as Grade 2 and 45% as Grade 3. Among molecular subtypes, Normal-Like was the most prevalent (27%). GATA-3 expression was positive in 66% of cases and was particularly strong (3+) in the Luminal B subtype. A statistically significant relationship was found between GATA-3 expression and both tumor type (p=0.026) and molecular subtype (p=0.001). SOX-10 expression was detected in 85% of cases, with higher positivity in basal-like tumors. Although no statistically significant association was observed between survival time and GATA-3 or SOX-10 expression, longer survival was more frequently observed in cases with Luminal A subtype and GATA-3 positivity. In conclusion, GATA-3 and SOX-10 are valuable biomarkers with potential prognostic significance and contribute to the molecular classification of canine mammary tumors.