In ovarian, pancreatic, biliary, esophageal, gastric, and colorectal/appendiceal adenocarcinomas, MUC5AC+/MUC1− is typically detected in PMOC tissues, whereas MUC5AC+/MUC1+, MUC5AC−/MUC1+, and MUC5AC−/MUC1− are detected in pancreatic and esophageal, biliary, and gastric and lower gastrointestinal adenocarcinomas, respectively [25]. This evidence concerns the gene MUC1 and appendix adenocarcinoma.