Melanomas are a tumor of the melanocyte, the skin cell that produces pigment which gives the skin and hair its characteristic color. Melanomas are common in aging gray horses, with an incidence of 80% in gray horses older than 15 years old. Common areas for the development of melanomas include under the tail, around the genitalia, in the parotid gland region, on the lips and eyelids. With time, melanomas can enlarge and invade local tissue and metastasize. Large melanomas can interfere with normal body function, such as urination and defecation. Local melanomas can metastasize to distant sites of the body, including internal organs. The clinical signs associated with metastasis vary according to the organ involved.
While melanomas are very common in gray horses, we believe that they are less frequent and less likely to occur in gray Quarter Horses than in other breeds. Our goal in this project is to look at genetic factors in gray Quarter Horses, to identify the ones that protect some horses from melanoma development. Once we have identified these factors we will be able to perform a DNA test on gray horses prior to the development of tumors, or when they are very small, to identify horses that are at risk for more invasive or metastatic tumors and treat these horses early. In order to achieve this goal, we need the help of horse owners that have gray Quarter Horses, with and without melanomas. By getting involved in our research, you will be assisting us to help gray horses with melanoma.
For more information about the project, including how to get involved, please email Dr. Raffaella Teixeira.