An experimental transplantable osteosarcoma with spontaneous pulmonary metastasis in hamsters

Animal models of osteosarcoma with spontaneous pulmonary metastasis which retain metastatic capacity and osteoid formation after serial passages have been reported infrequently. In this communication we describe some biological features of a transplantable osteosarcoma, Os515, induced by BK-virus in Syrian golden hamsters. The subcutaneously transplanted tumours in 2-week-old animals grew progressively until death, with a mean survival time of 32 days. Distant metastases occurred only in the lungs in all animals. The histological appearance was osteosarcoma of osteoblastic type. Enzyme-histochemical staining showed alkaline phosphatase activity in many cells and beta-glucuronidase activity in few cells. Tumours transplanted intramuscularly in the hind limbs were amputated radically at 5 or 11 days. A small number of animals died from lung metastases without local relapse during the observation period of 140 days after grafting. All the control hamsters bearing unamputated tumours died much earlier. Necropsy revealed large metastatic nodules in the lungs of limb-amputated animals and small diffuse nodules in the lungs of untreated control animals. The development of lung metastases was monitored by soft X-ray without sacrificing the animals. This model will be useful in studies of mechanisms of metastasis and for the experimental treatment of osteosarcoma.