MUC13 is a transmembrane mucin expressed on epithelial and hemopoietic cells, particularly in the gastrointestinal tract and trachea 1. The protein contains an N-terminal mucin repeat domain, epidermal growth factor-like sequences, and a cytoplasmic tail that undergoes homodimerization 1. MUC13 functions in intestinal barrier maintenance and host-microbe interactions 2. In pathological contexts, MUC13 plays critical roles in cancer progression: RUNX1 transcriptionally upregulates MUC13 to activate Wnt/β-catenin signaling, promoting colorectal cancer metastasis 3, while GCNT3 regulates MUC13 to activate GSK3β/β-catenin signaling in hepatocellular carcinoma 4. MUC13 overexpression disrupts cellular polarity, facilitates epithelial-mesenchymal transition, and contributes to chemoresistance 5. In mucosal defense, MUC13 knockdown increases pathogenic bacterial adhesion 6, while microRNA-mediated suppression of MUC13 compromises intestinal barrier integrity 7. Genetically, the MUC13 rs6765247 polymorphism associates with increased asthma exacerbations, particularly in smokers 8. Thus, MUC13 functions both as a protective barrier component and as an oncogenic driver of cancer progression through β-catenin pathway activation.