RBP5 (retinol binding protein 5) is primarily involved in intracellular transport of retinol and fatty acid binding 1. This cytosolic and nuclear protein facilitates retinoid metabolism and cellular signaling pathways essential for normal cell differentiation and proliferation. Mechanistically, RBP5 functions as part of retinoid acid metabolism networks. In keloids, RBP5 inhibition by retinoic acid promotes differentiation of pro-inflammatory fibroblasts to mesenchymal fibroblasts, reducing collagen secretion 2. RBP5 is also a component of tertiary lymphoid structure (TLS)-associated gene signatures in pancreatic cancer, contributing to immune infiltration patterns and chemotherapeutic sensitivity 34. Additionally, RBP5 participates in retinoid acid metabolism during neural development, influencing neurodevelopmental processes in zebrafish 5. Disease relevance is significant across multiple conditions. In hepatocellular carcinoma, RBP5 down-regulation is associated with aggressive tumor features, poor differentiation, and reduced overall survival 1. In pancreatic cancer, RBP5 expression within TLS correlates with improved survival and enhanced chemotherapy sensitivity 4. RBP5 also serves as a component in plasma proteomic scores predicting liver fat content and cardiovascular-kidney-metabolic disease risk 6. Clinically, RBP5 represents a potential biomarker for cancer prognosis and treatment selection, with therapeutic implications in keloid management through retinoic acid-mediated RBP5 inhibition.