Lok et al. [87] examined the immunohistochemical features of 41 cases of ICC and 60 cases of pancreatic ductal adenocarcinoma and reported that the S100P(−)/pVHL(+)/MUC5AC(−)/CK17(−) pattern was indicative of ICC, while the S100P(+)/pVHL(−)/MUC5AC(+)/CK17(+) and S100P(+)/pVHL(−)/MUC5AC(−)/CK17(+) patterns were indicative of pancreatic ductal adenocarcinoma. This evidence concerns the gene MUC5AC and pancreatic ductal adenocarcinoma.