Claudin 18.2 [MD415R]

The claudin superfamily consists of many structurally related proteins in humans. These proteins are important structural and functional components of tight junctions in paracellular transport. Claudins are located in both epithelial and endothelial cells in all tight junction-bearing tissues. Claudin 18 (CLDN18) is a protein forming tight junctions in epithelial cells, primarily in lungs (Claudin 18.1) and in the stomach (Claudin 18.2), crucial for barrier function, with the gastric isoform (Claudin 18.2) becoming a key biomarker and target for gastric and gastroesophageal junction (GEJ) cancers. It helps maintain cell polarity and acid resistance in the stomach, but its aberrant expression in gastric/GEJ adenocarcinomas makes it a target for monoclonal antibody therapies like zolbetuximab, identifying patients eligible for treatment.