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 the growth of epithelial tissue, cell differentiation, and formation of the nervous system. Altered RARB activity has been linked to cancers such as skin, lung, and breast cancers, as well as developmental disorders, and is being studied for potential retinoid-based therapies.