FMO2 (flavin-containing dimethylaniline monoxygenase 2) is a multifunctional enzyme that catalyzes the oxidative metabolism of xenobiotics, including therapeutic drugs and insecticides containing nitrogen and sulfur nucleophiles 12345. Beyond its traditional metabolic role, FMO2 exhibits diverse protective functions across multiple tissues. In hepatocytes, FMO2 prevents nonalcoholic fatty liver disease by directly binding SREBP1 and inhibiting its translocation from the endoplasmic reticulum to Golgi apparatus, thereby suppressing de novo lipogenesis independent of its enzymatic activity 6. In cardiac tissue, FMO2 provides cardioprotection against ischemic injury and doxorubicin-induced cardiomyopathy through its disulfide bond catalytic activity, functioning as a chaperone that promotes proper protein folding and reduces ER stress-induced apoptosis 78. FMO2 also promotes angiogenesis by regulating N-acetylornithine metabolism, which inactivates NOTCH1 expression 9. In cancer contexts, FMO2 expression is associated with improved prognosis in breast cancer and enhanced response to immunotherapy in hepatocellular carcinoma through modulation of the tumor microenvironment 1011. These findings establish FMO2 as a pleiotropic protein with both enzymatic and non-enzymatic functions critical for cellular homeostasis and disease prevention.