MUC4 and extrahepatic bile duct carcinoma: One of the anti-MUC4 TR antibodies, 8G7, has served as a valuable reagent to study the expression of the MUC4 mucin in various tissues and unravel its involvement in various malignancies including, pancreatic [12], [18], gastric [19], cervical [20], ovarian cancers [21], extra hepatic bile duct carcinoma [22], colangiocarcinoma [23], and cutaneous squamous cell carcinoma.