Oral malignant melanoma (OMM) is the most common tumor that arises in a dog’s mouth. Canine OMM is locally aggressive and has a high risk of spread (metastasis) to other organs such as lymph nodes, lungs, and the brain. Once it spreads to other organs, treatment options are limited. Melanoma vaccine and chemotherapy have been used to treat advanced-stage melanomas; however, they only show a 30-40% response rate. In humans, melanoma is known to have genomic mutations in about 50% of patients and targeted therapy for this mutation is one of the main treatment options for advanced-stage melanomas. In veterinary medicine, targeted therapy has not been evaluated yet since canine OMM does not carry the same mutations as human melanomas.

In this study, the researchers will compare genomic mutations between primary OMM and lymph nodes that have cancer spread from the primary mouth tumor. They will use archived tissue samples from 15 dogs that were previously treated with surgical removal of the primary oral mass and lymph node extirpation (removal or destruction). These samples will be submitted to Vidium Animal Health for genomic analysis. The results of this study may provide insights as to what mutations are driving the highly metastatic nature of canine OMM. Knowing the mutation status at the lymph node may also help the researchers investigate new therapeutic targets since the majority of dogs eventually succumb to cancer spread even after surgical resection of the oral mass.