Immunohistochemical characterization of endocrine cells in experimental exocrine pancreatic cancer in the Syrian golden hamster.

Fifty exocrine pancreatic adenocarcinomas and 57 benign tumors induced in Syrian hamsters byN-nitrosobis (2-oxopropyl)amine (BOP) were examined for the presence of argyrophil cells antiinsulin, -glucagon,-somatostatin, -pancreatic polypeptide (PP), -gastrin/CCK, -vasoactive intestinal polypeptide (VIP), and - neuron-specific enolase (NSE) reactive cells. Argyrophil— and antihormone-reactive cells were found in the normal pancreatic ducts and in the acini, as well as in hyperplastic and atypical ducts/ductules, tubular complexes, benign lesions, and in 80% of ductal adenocarcinomas. Insulin and antiNSE-reactive cells were the most common, followed in decreasing frequency by glucagon, somatostatin, and PP cells. Antigastrin-/CCK- and-VIP-reactive cells were found in two cases. Argyrophil cells were present in about 60% of the tumors with Grimelius staining and in 55% of those with Churukian-Schenk staining. Insulin cells were seen in ductal cancer that had grown into a lymph node and in the lymph node metastases of another cancer. A novel finding was the presence of argyrophil and insulin cells within the lumen of some malignant glandular structures. Coexistence of several peptide cells was found in 52% of the cancers. The presence of argyrophil and hormoneproducing cells in induced pancreatic ductal/ductular lesions further strengthens the existence of a close developmental relationship between exocrine and endocrine cells of the pancreas. Key Words: Pancreatic cancer; experimental; Syrian hamster; endocrine cells; argyrophil cells; immunohistochemistry; pancreatic peptides; BOP.