Osteogenic induction by cell-free material from murine osteosarcoma and its cultured cell line.

A bone-inducing factor was detected in murine osteosarcoma and its cultured cells. The factor was partially purified from the osteosarcoma and its biological properties were examined. The ectopic formation of the bone with hematopoietic marrow was observed in situ histologically 4 weeks after inoculation of the cell-free material intramuscularly or subcutaneously. Non-osteogenic tumors do not produce this factor. This factor seems to be a protein which is relatively resistant to heating yet labile to mechanical shaking.