The antitumor effects of IFN- beta against human renal cell carcinoma in athymic nude mice

IFN-beta was more active than recombinant interferon-alpha (rIFN-alpha) and interferon-gamma (rIFN-gamma) in a human renal cell carcinoma transplanted in nude mice. In 3 out of 5 mice, the tumor completely disappeared and viable tumor cells were not observed at a daily dose of 5 x 10(5) U/mouse. Combination with anti-asialo GM1 antibody did not influence the tumor growth inhibition by IFN-beta. Mononuclear cells around damaged cancer cells were found not to be macrophages. Although the role of mononuclear cells remained unknown, the antitumor activity of IFN-beta seemed to depend on its direct cellular action. IFN-beta may be a useful agent in some renal cell carcinomas.