Failure of interferon to inhibit radiation-induced osteosarcomas in mice

The injection of murine interferon three times per week in dose levels of 1250, 5000, or 20,000 units, did not produce any significant antitumor effect against primary 239Pu-induced osteosarcomas, primary hematopoietic tumors or osteosarcoma implants in C57B1/6j mice. The interferon treatment was begun 94 days after the plutonium injection, which is well before the radiographic or microscopic appearance of neoplasia, and was continued until the moribund state or death. The average radiation dose to the skeleton at the time of first treatment was approximately 300 rads. The largest dose of interferon studied, 20,000 units/injection, was equivalent to approximately 5 x 106 units/injection (based on body surface) or 70 x 106 units/injection (based on body weight) for a 70 kg, 5' 10'' person