Antitumor effect of human leukocyte interferon on human osteosarcoma transplanted into nude mice.

We studied the effect of human leukocyte interferon (HuIFN-alpha) on a human osteosarcoma (OS-OH) transplanted and passed serially in athymic mice. The growth of OS-OH was strikingly inhibited by HuIFN-alpha (50,000 IU/mouse), regardless of whether the interferon treatment was initiated 24 hr after tumor inoculation or 2 weeks later, when tumors had grown to an appreciable size (4-6 mm). The antitumor effect of HuIFN-alpha was found to be dose-dependent and a daily administration of HuIFN-alpha (50,000 IU/mouse) all but completely arrested the tumor growth.