In dogs, mammary gland tumors are hormone-dependent and are more common in females. Their histological pattern is complex, involving cartilage and bone tissue as well as different types of cells (luminal epithelial, myoepithelial and mesenchymal). Although still unknown, it is thought that cancer stem cells (CSCs) may play an important role in the development of this pattern.
This review was based on research carried out on SCCs from canine mammary tumours and sought to characterize them, create hypotheses about their hierarchical structure and evaluate studies on their metabolism.
In veterinary medicine, cancer stem cells were first diagnosed in osteosarcoma (Wilson et al., 2008). There are several gold standard methods for assessing these cells. In canine mammary adenocarcinoma, for example, they can be identified in a number of ways, in particular by considering their expression of the surface markers CD44 and CD24, using flow cytometry.
The metabolic properties of cancer stem cells have also been assessed. Despite the lack of data on their relevance in canine mammary tumors, human medicine has already demonstrated the importance of amino acid and fatty acid metabolism in the maintenance of SCCs; it is known, for example, that proline metabolism is involved in the self-renewal capacity of human mammary gland cancer stem cells.
In veterinary medicine, some isolates from spontaneous canine mammary carcinomas have been shown to be highly sensitive to metformin, an antidiabetic that also seems to have some anti-tumor effect. Even so, more studies on the metabolism of cancer stem cells are needed, as the findings are crucial for the emergence of new and effective therapies in the field of veterinary oncology.
M. Michishita (2020). Understanding of tumourigenesis in canine mammary tumors based on cancer stem cell research. The Veterinary Journal, 265, 105560. http://dx.doi.org/10.1016/j.tvjl.2020.105560
