[Biological characterization of a hamster osteosarcoma Os 515--development of lung metastasis]

Biological characterization of a transplantable hamster osteosarcoma Os515 which had been induced by BK virus was attempted, and usefullness of this tumor was confirmed as an experimental model of treatment of osteosarcoma. All the hamsters with this tumor died of spontaneous lung metastasis. The chest X-ray picture of a tumor-bearing hamster visualized diffuse metastasis in the whole lungs 30 days after transplantation. The development of lung metastases was monitored by chest X-ray after marginal excision of subcutaneously transplanted tumors or after radical disarticulation of a tumor-bearing hind limb. Slow-growing nodular lung metastases were seen on X-ray pictures when the subcutaneous tumors were resected 1 or 2 weeks after transplantation, whereas fast-growing diffuse metastases were seen when the tumors were not resected at all or resected 3 weeks after transplantation. Nodular lung metastases occurred in a small number of animals long after the early radical disarticulation of a tumor-bearing leg.