SAT1 (spermidine/spermine N1-acetyltransferase 1) is an X-linked polyamine-metabolizing enzyme that catalyzes acetylation of polyamines, particularly spermidine and norspermidine 1. As a rate-limiting enzyme in polyamine catabolism, SAT1 converts spermidine and spermine back to putrescine, providing fine attenuation of intracellular polyamine concentrations and regulating polyamine export 23. Mechanistically, SAT1 functions through multiple pathways. As a p53 transcriptional target, SAT1 activation induces lipid peroxidation and ferroptosis via ALOX15-dependent mechanisms, suppressing tumor growth 3. In triple-negative breast cancer, SAT1 stabilizes YBX1 protein through the deubiquitylation machinery, suppressing autophagy via mTOR stabilization and driving cancer progression 4. Additionally, SAT1-mediated production of N1-acetylspermidine promotes immune suppression through SRC signaling-dependent macrophage polarization in hepatocellular carcinoma 5. Clinically, SAT1 dysregulation associates with multiple diseases. High SAT1 expression correlates with worse prognosis in triple-negative breast cancer and acute myocardial infarction 64. Conversely, SAT1 dysfunction contributes to systemic lupus erythematosus pathogenesis 7, while elevated SAT1 impairs regulatory T cell function in chrX cutaneous inflammation 8. These findings position SAT1 as a therapeutic target across cancer and inflammatory diseases.