Extracellular Vesicles as Emerging Tools in Canine Mammary Tumors: Potential Applications and Perspectives.

Breast cancer is one of the most prevalent malignancies in women worldwide and the most common malignant tumor in unspayed female dogs, highlighting the comparative relevance of this disease across these species. The release of EVs is increased in mammary tumors compared to normal tissue, with the quantity generally correlating with the tumor's histological grade and aggressiveness. EVs carry a varied molecular load, mainly composed of proteins, RNAs, including microRNAs (miRNAs), lipids, and nucleic acids. These contents reflect the cell of origin and are related to the tumor profile (adenoma, adenocarcinoma, or carcinoma). EVs influence biological processes such as cell proliferation, migration, and invasion, as well as interfere with the immune response, potentially favoring tumor growth, disease progression, and metastasis formation, since they act as intercellular messengers, modulating the tumor microenvironment. Despite substantial advances in research related to EVs in human breast cancer, there is still a significant lack of studies focused on veterinary oncology, especially regarding the association of EVs with CMTs. In this context, this review aimed to compile the evidence available to highlight the importance of EVs in CMTs in female dogs, especially as promising tools for innovative strategies in veterinary medicine.