IFNW1 encodes interferon omega-1, a type I interferon that functions as an antiviral and immunomodulatory cytokine. The protein exhibits potent antiviral activity against DNA and RNA viruses and binds to the same class I interferon receptor complex (IFNAR) as IFN-α and IFN-β 12. IFNW1 demonstrates antiproliferative effects against tumor cell lines and stimulates natural killer cell activity while enhancing MHC class I antigen expression 1. The gene shows distinct expression patterns in cancer, being significantly downregulated in glioma tissues compared to normal tissue, with higher expression associated with improved survival outcomes 3. Clinically, autoantibodies against IFN-ω are found in patients with severe COVID-19, particularly in elderly individuals, and these neutralizing antibodies impair the antiviral response to SARS-CoV-2 45. IFNW1 polymorphisms are associated with immune-related adverse events in cancer patients receiving PD-1/PD-L1 checkpoint inhibitors 6. The protein's antigenic properties are distinct from other interferons, as it does not cross-react with antibodies against IFN-α, -β, or -γ 1. These findings highlight IFNW1's dual role in antiviral immunity and cancer biology, with potential therapeutic and diagnostic applications.