ERO1A is an endoplasmic reticulum (ER) oxidoreductase that catalyzes disulfide bond formation in secretory proteins by reoxidizing protein disulfide isomerase (PDI) 1. Following this reoxidation, ERO1A transfers electrons to molecular oxygen via FAD, generating reactive oxygen species (ROS). The enzyme is essential for proper folding of immunoglobulins and plays a role in ER stress-induced apoptosis through activation of the inositol 1,4,5-trisphosphate receptor. ERO1A is involved in retrotranslocation of cholera toxin during V. cholerae infection. ERO1A is upregulated across multiple cancer types, where it drives malignant phenotypes through distinct mechanisms. In endometrial cancer, macrophage-secreted KYNU promotes ERO1A expression via SOD2-mediated redox shifts, activating the unfolded protein response to support tumor survival 2. In colorectal cancer, ERO1A-positive epithelial cells interact with cancer-associated fibroblasts and macrophages to enhance proliferation, migration, and metastasis 3. In bladder cancer, ERO1A suppresses ALOX5 phosphorylation to activate JAK-STAT signaling and inhibit autophagy 4. High ERO1A expression in lung cancer associates with worse outcomes following neoadjuvant immunotherapy 5, and ERO1A emerges as an independent prognostic indicator in female lung adenocarcinoma 6. Clinically, ERO1A ablation enhances anti-tumor immunity and PD-1 checkpoint blockade efficacy by inducing immunogenic cell death 5. In SEPN1-related myopathy, ERO1A inhibition or treatment with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) rescues mitochondrial function and muscle weakness 7. In cardiac hypertrophy, ERO1A inhibition with the compound EN460 normalizes sarcoplasmic reticulum redox state and reduces proarrhythmic calcium waves 8.