IN-SITU HYBRIDIZATION SHOWS DISTINCT PATTERNS OF MUCIN GENE-EXPRESSION IN NORMAL, BENIGN, AND MALIGNANT PANCREAS TISSUES

Background & Aims: Northern blotting and immunohistochemistry have shown cell-specific patterns of mucin gene expression in the pancreas and alterations associated with neoplastic transformation. The aim of this study was to determine the presence of mucin transcripts at the single cell level in tissue samples from normal pancreas and benign and malignant pancreatic proliferative lesions. Methods: In situ hybridization with S-35-labeled oligonucleotides was performed on sections of paraffin-embedded tissues. Results: Acinar cells express only MUC1. Normal pancreatic ducts show homogeneous expression of MUC1 and MUC5B and heterogenous expression of MUC3. MUC2, MUC4, and MUC5AC are generally undetectable in all cells of normal pancreas tissues. Pancreas cancers generally express MUC1, MUC3, MUC4, MUC5B, and MUC5AC. Obstructive chronic pancreatitis adjacent to pancreas cancers shows the same pattern of mucin gene expression as normal ducts. In areas of papillary hyperplasia, altered expression of MUC3, MUC5B, and MUC5AC is observed. Conclusions: In situ hybridization has confirmed that neoplastic transformation of the exocrine pancreas is accompanied by changes in mucin gene expression. Although this type of change is not restricted to cancer cells, the findings of this study suggest that analysis of mucin gene expression may be of value in the differential diagnosis of pancreatic lesions.