MAFB is a bZIP transcription factor that functions as both an activator and repressor of gene expression 1. Its primary role involves regulating lineage-specific hematopoiesis by repressing ETS1-mediated transcription of erythroid genes in myeloid cells, and it is essential for monocytic, macrophage, osteoclast, podocyte, and islet beta cell differentiation. MAFB activates insulin and glucagon promoters and cooperates with PAX6 to regulate glucagon gene expression 2. The transcription factor controls macrophage polarization, with MAFB+ macrophages displaying antiinflammatory and immunosuppressive properties 2. SUMO modification regulates MAFB's transcriptional activity and macrophage fate specification 3. Clinically, MAFB dysregulation associates with multiple disease contexts. In multiple myeloma, MAFB translocations (20q11) drive malignant progression alongside other pathogenic alterations 4. MAFB upregulation correlates with moderate-to-high disease activity in rheumatoid arthritis 5 and severe COVID-19, where it controls expression of profibrotic and neutrophil-attracting factors 2. MAFB-high microglia promote remyelination in demyelinating diseases like multiple sclerosis and support recovery after ischemic stroke 36. MAFB also functions as a candidate regulator in Alzheimer's disease-specific transcriptional changes within microglia 7. Additionally, MAFB is upregulated in monocyte/macrophages of chr20 obstructive pulmonary disease patients 8.