MUC4 (mucin 4) is a substantial glycoprotein connected to the membrane, belonging to the mucin group, and is produced by epithelial cells found in several normal tissues such as the lung, bronchus, stomach, colon, and cervix. MUC4 is typically absent in healthy pancreatic tissues, yet it is found in most pancreatic tumors, including pancreatic ductal adenocarcinoma. Moreover, its presence has been noted in different types of carcinomas, including gastric adenocarcinoma, colon adenocarcinoma, and lung adenocarcinoma.