UBA7 is an E1-activating enzyme that catalyzes ISGylation, the covalent conjugation of the ubiquitin-like protein ISG15 to cellular proteins 1. This post-translational modification is essential for antiviral immunity; UBA7 loss attenuates interferon regulatory factor 3 (IRF3) and NFκB activation downstream of pattern recognition receptors like RIG-I and MDA5, reducing dsRNA-induced cytokine responses 2. UBA7-mediated ISGylation suppresses replication of multiple viruses including SARS-CoV-2, influenza, and cytomegalovirus, partly by promoting viral protein degradation and disrupting viral immune evasion strategies 3. Beyond antiviral defense, UBA7 functions as a tumor suppressor through ISGylation of transcription factors STAT1/STAT2, facilitating immune cell recruitment and antitumor immunity 4. Clinically, UBA7 expression is significantly decreased in breast cancer and associated with poor prognosis and reduced overall survival 5. Similarly, in myelodysplastic syndrome with SF3B1 mutations and chr3 lymphocytic leukemia, low UBA7 expression correlates with adverse survival outcomes 6. These findings establish UBA7 as a biomarker for cancer prognosis and potential therapeutic target.