RBP1 (retinol binding protein 1) is a cytoplasmic protein that functions as an intracellular retinoid chaperone, accepting retinol from the transport protein STRA6 and facilitating retinol uptake, storage, and retinoid homeostasis 1. RBP1 binds retinol and retinal with high affinity, protecting retinoids from non-specific oxidation and delivering them to enzymes for retinoic acid (RA) biosynthesis 2. This function is critical for maintaining all-trans retinoic acid (ATRA) homeostasis, which regulates gene transcription through nuclear receptors and controls physiological processes including development and immune response 3. Clinically, RBP1 dysregulation is associated with multiple diseases. RBP1 expression is reduced in prevalent cancers including breast cancer, correlating with decreased ATRA levels and increased epithelial cell proliferation 2. Conversely, RBP1 is significantly upregulated in oral squamous cell carcinoma, where it promotes cancer progression through the RBP1-CKAP4 axis by activating oncogenic autophagy 4. In ocular pathology, RBP1 is part of the retinal pigment epithelium signature gene set essential for maintaining photoreceptor viability and visual cycle function 5. Dysregulation of RBP1 and ATRA has been implicated in various genetic disorders, endometriosis, and heart failure 3. Therapeutic restoration of RBP1 expression and endogenous ATRA production may benefit disease management 2.