AZIN1 (antizyme inhibitor 1) is a critical regulator of polyamine biosynthesis that functions by counteracting antizyme-mediated inhibition of ornithine decarboxylase (ODC). As an enzymatically inactive ODC homolog, AZIN1 competes with ODC for antizyme binding, preventing antizyme-dependent ODC degradation and restoring formation of catalytically active ODC homodimers 1. This mechanism positively regulates polyamine production, which is essential for cell proliferation and protein synthesis 2. AZIN1 undergoes adenosine-to-inosine RNA editing that enhances its function, particularly during stress responses and recovery mechanisms in tissues like the kidney 3. The protein plays significant roles in cancer biology, with overexpression associated with aggressive tumor phenotypes in medulloblastoma 4, endometrial cancer 5, and osteosarcoma 6. In these malignancies, AZIN1 promotes cell cycle progression through MYC signaling pathways and contributes to immunotherapy resistance 6. AZIN1 expression is also modulated by glucocorticoids as part of stress responses 7. The protein's role in maintaining polyamine homeostasis makes it a potential therapeutic target, as disrupting AZIN1 function can impair tumor growth and enhance treatment sensitivity 6.