CEBPB (CCAAT enhancer binding protein beta) is a transcription factor that regulates diverse cellular processes with significant implications in disease pathogenesis. Primary Function: CEBPB acts as a DNA-binding transcription factor controlling gene expression in response to cellular stress and differentiation signals. It exists as multiple isoforms, including the liver-enriched activator protein (LAP), with distinct regulatory roles 1. Mechanism: CEBPB functions through heterodimerization and controls transcriptional programs in multiple cell types. In endothelial cells, CEBPB promotes endothelial-to-mesenchymal transition (EndoMT) and regulates expression of pro-fibrotic factors like Galectin 3 23. CEBPB regulates myeloid lineage differentiation—its upregulation diverts bone marrow progenitors toward immunosuppressive myeloid lineages, while suppression promotes immunostimulatory output 4. In immune cells, CEBPB expression is post-translationally controlled by the COP1 ubiquitin ligase; dysregulation drives pro-inflammatory and neurodegeneration-related programs in microglia 5. Disease Relevance: CEBPB contributes to multiple pathologies including gastric cancer progression via EndoMT mechanisms 2, glioblastoma progression through M2 macrophage recruitment 6, pulmonary fibrosis via senescent endothelial cell signaling 3, and chemoresistance in gastric cancer 7. In triple-negative breast cancer, the LAP isoform controls myeloid-derived suppressor cell development through glycolysis regulation 1. Clinical Significance: CEBPB represents a potential therapeutic target for modulating immunosuppression and EndoMT-related pathologies across cancer and fibrotic disease contexts.