F11R (F11 receptor), also known as junctional adhesion molecule-A (JAM-A), is a transmembrane glycoprotein of the immunoglobulin superfamily that plays critical roles in cell-cell adhesion and barrier function 1. The protein is constitutively expressed in tight junctions of endothelial and epithelial cells, as well as on circulating platelets and leukocytes 2. F11R maintains endothelial barrier integrity by promoting claudin-5 expression through C/EBP-α transcriptional regulation, with genetic deletion in mice causing increased vascular permeability 1. In inflammatory contexts, pro-inflammatory cytokines induce de novo F11R transcription and translation in endothelial cells via NF-κB and JAK/STAT pathways, facilitating platelet adhesion to inflamed endothelium—a crucial early step in atherogenesis 3. F11R also regulates smooth muscle cell migration and proliferation in atherosclerotic plaques 4. In cancer, F11R exhibits tissue-specific roles, with knockdown studies showing reduced proliferation, invasion, and enhanced apoptosis in pancreatic cancer cells 5. Additionally, F11R undergoes ADAR-mediated RNA editing in gastric and colorectal cancers, potentially serving as a diagnostic biomarker 6. The protein's diverse functions span vascular barrier maintenance, inflammatory responses, and cancer progression, making it a potential therapeutic target.