The establishment of a cell line derived from a human osteosarcoma after transplantation into nude mice is reported. Many of the cells were of the fibroblastic type (fusiform type), and the doubling time was 30.75 hours. These cells interdigitated with each other and showed loss of contact inhibition. Blue granules were seen in the cytoplasm following the use of Jacobson's stain. On electron microscopy the cells showed microfilaments in the cytoplasm. Alkaline phosphatase was weakly positive and acid phosphatase was moderately positive. Chromosomal analysis showed a human pattern. This cell line should provide a useful model for investigation of human osteosarcoma.
