Chemotherapeutic effect on osteosarcoma on basis of collagen analysis: a proposal of the induction of osteosarcoma differentiation.

The authors studied effect of chemotherapy on osteosarcoma by collagen analysis. As a result of this case study we propose the induction of osteosarcoma differentiation by chemotherapy. Treatment of a conventional osteosarcoma with two intra-arterial infusions of cisplatin and the T-12 protocol of Rosen resulted in sclerotic changes and good margination accompanied by the disappearance of the soft-tissue component from the X-rays. More than 90% tumour destruction was histologically demonstrated; tumour bone and osteoid increased after the chemotherapy, and the viable area of the tumour resembled an osteoblastoma. Before the chemotherapy, immunolocalization determined collagen types I and V to be diffusely present in the bone and osteoid. After the chemotherapy, the antibody to type I collagen was diffusely present, but the antibody to type V collagen occurred only on the surface of the increased bone and osteoid as in normal bone. When osteosarcoma cells were treated in vitro with methotrexate or cisplatin, collagen production increased significantly. It is thus believed that tumour cells were directly stimulated with these chemotherapeutic agents to produce collagen. The findings suggested that some anticancer agents might not only be cytotoxic to but also differentiate osteosarcoma cells.