Alpha 2 interferon in the prevention of N-nitroso-methyl urea induced breast cancer in rats.

Human interferons have been shown to be effective treatment for hairy cell leukaemia and are now commercially available. Their role in treatment of solid tumours has yet to be established. This study assessed the value of alpha 2 interferon (IFN) in an experimental breast cancer model. Four groups of female Sprague-Dawley rats were studied. The first received three intravenous injections (7 mg/kg) of N-nitroso-methyl urea (NMU) at weeks 0, 3 and 7. The second received the same NMU dosage regime plus IFN (100,000 IU, twice weekly for 3 weeks). A third received IFN alone and the fourth was a control group receiving three intravenous injections of normal saline. At week 16, 19 of 20 rats in the NMU alone group had developed tumours significantly more than four of 15 rats with tumour in the NMU plus IFN group (P less than 0.001). Both the mean tumour number/rat and the mean tumour weight/rat was significantly more in the NMU group than the NMU plus IFN group P less than 0.05). No rats in the IFN alone or control group developed tumour. These data suggest that IFN prevents carcinogen induced breast cancer in rats. It may have a role in the prevention and treatment of human breast cancer.