IFNA1 and cancer: However, IFN-induced skin, neurological, endocrine, and immune toxicities have been a factor that restrict the amounts of interferon that can be used for effective cancer therapy.53 In order to reduce the toxicity from a single-drug treatment and bypass the issue of immune tolerance, IFNs are usually combined with other immunotherapeutic drugs, chemotherapy drugs, or molecular-targeted antitumor agents.