The biology of human cells in tissue culture. I. Characterization of cells derived from osteogenic sarcomas.

We have extensively characterized cell lines derived from six human osteosarcomas. The growth properties of these cultures were compared to those of fibroblastic cultures derived from skin of osteosarcoma patients and skin of bone-marrow of normal individuals. Each tumor-derived line showed some but not all of the abnormal growth properties usually associated with malignant transformation, indicating that tumor cells rather than normal stromal cells had in fact been cultured. The parameters measured included saturation density, cell morphology, growth pattern, growth on contact inhibited monolayers of normal fibroblastic or epithelial cells and tumorigenicity in immunosuppressed mice. Although the skin fibroblasts from the osteosarcoma patients appeared normal in vitro, they showed a greater ability to grow in immunosuppressed mice than did normalfibroblasts. This observation suggests that all fibroblasts of osteosarcoma patients may have an increased propensity for malignant transformation.