RARB (Retinoic Acid Receptor Beta): RARB is a nuclear receptor that binds retinoic acid, a metabolite of vitamin A. It plays a key role in regulating gene expression during development, particularly in epithelial tissue growth, cell differentiation, and nervous system formation. Altered RARB activity has been linked to cancers such as skin, lung, and breast, as well as developmental disorders, and is being studied for potential retinoid-based therapies.