RXRG (retinoid X receptor gamma) is a nuclear receptor that functions as a ligand-activated transcription factor, binding 9-cis retinoic acid and forming heterodimers with retinoic acid receptors to regulate gene expression through retinoic acid response elements 1. RXRG plays critical roles in diverse biological processes: it regulates prefrontal cortex patterning and PFC-mediodorsal thalamus connectivity during primate brain development 1, and acts as a cell-intrinsic checkpoint controlling group 2 innate lymphoid cell activation by maintaining cholesterol efflux and suppressing inflammatory responses 2. In cancer biology, RXRG exhibits context-dependent functions—it suppresses neural crest stem cell programs that drive melanoma drug resistance 3, serves as an independent favorable prognostic biomarker in ER-positive breast cancer 4, and correlates with improved outcomes in thyroid carcinoma through immune modulation 5. RXRG also regulates photoreceptor development, as NR2E3 mutations impairing RXRG expression cause retinal degeneration 6. Genetically, RXRG variants associate with type 2 diabetes susceptibility in East Asian populations 7 and have been identified in familial prolactinoma 8. These findings establish RXRG as a multifunctional nuclear receptor with tumor-suppressive properties and immune-regulatory functions relevant to cancer, metabolic, and neurodevelopmental diseases.