MUC6 is a gel-forming mucin primarily expressed in gastrointestinal epithelium that plays a crucial role in maintaining epithelial barrier integrity and gastric mucosal protection 1. The protein functions through extensive glycosylation and interaction with trefoil factor 2 (TFF2), which stabilizes the gastric mucus barrier via lectin interactions with specific glycotopes 2. MUC6 modulates protective mucus composition in response to acid secretion, bacterial presence, and noxious agents 1. Genetically, MUC6 variants contribute to peptic ulcer disease susceptibility through roles in Helicobacter pylori infection response and gastric acid secretion 3. A variable number tandem repeat (VNTR) polymorphism within MUC6 has been associated with Alzheimer's disease tau pathology and may influence AP2A2 gene expression 4. MUC6 loss is frequently associated with gastric cancer development, with Muc6 knockout mice spontaneously developing pan-gastritis and invasive gastric tumors through Golgi stress-induced mitogen-activated protein kinase activation and aberrant mannose-rich glycosylation 5. Conversely, MUC6 upregulation serves as a biomarker in prostate cancer, and MUC6 glycoforms offer therapeutic targets 1. MUC6 expression is also useful diagnostically for identifying gastric-type adenocarcinoma in endocervical lesions, though with moderate sensitivity and specificity 6.