Expression and localization of MUC1, MUC2, MUC5AC and small intestinal mucin antigen in pancreatic tumors.

Alterations in the expression of mucin family members play an important role as well as alterations in oncogenes and onco-suppressor genes in carcinogenesis and progression of pancreatic cancer. We analyzed the expression and localization of MUC1, MUC2, MUC5AC and small intestinal mucin antigen (SIMA) in pancreatic tumors. MUC1 expression was observed in almost all samples, whereas MUC2 expression was not. MUC5AC expression was observed in 73.9% of the cancerous regions, 48.7% of the dysplastic regions and 72.0% of the hyperplastic regions but not in the normal pancreatic duct. SIMA expression was observed in 45.7% of cancerous regions, 17.9% of the dysplastic regions and 8.0% of the hyperplastic regions. Furthermore, stromal expression of MUC1, MUC5AC and SIMA was observed in 37.0%, 60.9% and 26.1% of the cancerous regions, respectively. Stromal expression of these mucins was not observed in the hyperplastic regions and normal pancreatic duct and was observed in only two dysplastic regions. The survival of pancreatic cancer patients with stromal expression of MUC1 or SIMA was worse than that of other patients (P=0.04). In conclusion, the localization of mucin expression, especially stromal expression of MUC1 or SIMA, might be a prognostic factor for patients with pancreatic cancer.