NR5A2 (nuclear receptor subfamily 5 group A member 2) is an orphan nuclear receptor that functions as a pioneer transcription factor regulating diverse biological processes including metabolism, cell differentiation, and disease pathogenesis 1. As a pioneer factor, NR5A2 can initiate transcription from closed chr1 by competing with DNA minor groove anchors in nucleosomes, using its conserved carboxy-terminal extension loop to destabilize nucleosome structure and facilitate DNA unwrapping 2. The protein regulates multiple metabolic pathways, including cholesterol metabolism and steroidogenesis, with hepatocyte-specific deficiency leading to inflammation, fibrosis, and pyroptosis through downregulation of ALDH1B1 and increased reactive oxygen species 3. In pancreatic cancer, NR5A2 exhibits context-dependent dual roles: promoting proliferation in differentiated cells while enhancing cancer stem cell properties through direct SOX2 upregulation and metabolic reprogramming toward oxidative phosphorylation 4. NR5A2 also demonstrates therapeutic potential in autoimmune diseases, with pharmacological activation inducing immune tolerance in type 1 diabetes by reprogramming macrophages and dendritic cells into anti-inflammatory phenotypes 5. The receptor is involved in steroidogenesis regulation, particularly in polycystic ovary syndrome where it works with other transcription factors to control androgen biosynthesis pathways 6.