Cellular and molecular mechansims of osteosarcoma

摘要

Osteosarcoma (OSA) is the most common bone tumor in the dog. Approximately 80-85 percent of primary malignancies that occur in the bones of dogs are osteosarcomas. It is estimated that up 10,000 new cases of canine osteosarcoma occur each year, although this number may be underestimated. Osteosarcoma is typically found in the appendicular skeleton, but axial osteosarcoma and extraskeletal sites also occur. This cancer commonly affects large to giant breed dogs with the median age at presentation ofseven years. Canine and human osteosarcoma are similar in many ways; the dog is an excellent spontaneous tumor model for the disease in human patients. The exact etiology of canine osteosarcoma is unknown. In humans with osteosarcoma mutations have beenobserved in the retinoblastoma (Rb) gene and in other tumor suppressor genes such as p53 and MDM2. Evidence suggests that similar derangements may occur in dogs with osteosarcoma. Osteosarcomas are highly metastatic, with spread most commonly to the lungs, although other metastatic sites such as bone, abdominal viscera and skin can occur. This discussion will review the current knowledge of the etiology of osteosarcoma and mechanisms involved in its metastasis.