Objectives: The aim of the present study was to characterize molecular targets for the prevention/diagnosis of pancreatic cancer using a chemically induced hamster pancreatic carcinogenesis model, in which background injuries to the parenchyma, for example, chronic pancreatitis or acinar atrophy, are limited.
Methods: Gene expression profiles in atypical hyperplasias were first investigated using a microarray technique. Immunohistochemical analyses of early lesions and invasive ductal carcinoma (IDC) were then conducted for MUC1, of which mRNA levels were prominent among the up-regulated genes, in contrast with the coexpression of epithelial-mesenchymal transition (EMT)-related proteins.
Results: Immunohistochemistry for MUC1 cytoplasmic domain (MUC1-CD), which was not detected in normal-like pancreatic ducts, was positive in the apical surfaces of the epithelia of hyperplasias with and without atypia and IDC areas with distinct tubular patterns. In contrast, cytoplasmic/nuclear positivity for MUC1-CD was observed in the invasive front of IDCs. The coexpression of EMT-related proteins, such as slug and vimentin, with cytoplasmic/nuclear MUC1-CD was also detected.
Conclusions: Alterations in the expression and subcellular localization of MUC1 represent a biphasic phenomenon, and the latter may be associated with EMT in pancreatic carcinogenesis in hamsters, which indicates that changes in MUC1 are important targets for pancreatic cancer prevention and chemotherapy.