The primary cause of death for dogs diagnosed with osteosarcoma (bone cancer) is the spread of the tumor to other sites in the body (metastasis). It is unknown why osteosarcoma cells are able to spread to distant sites and survive, as well as establish new tumors. In this project , researchers will examine the differences between standard osteosarcoma cell lines and daughter versions of these cell lines that have successfully completed specific tests that mimic steps in the process of metastasis occurring in the body. They will evaluate differences in the way they behave and respond to harsh conditions, as well as their gene expression patterns. Treatment for osteosarcoma has remained largely unchanged for over 30 years and improvement in patient outcomes has subsequently plateaued. Defining the most important mechanisms driving osteosarcoma metastasis will contribute to therapeutic advances that extend the lives of patients suffering with this devastating disease.