Immunocytochemical distribution of trypsinogen and pancreatic secretory trypsin inhibitor in normal and neoplastic tissues in man.

Immunoreactive trypsinogen and pancreatic secretory trypsin inhibitor (PSTI) were demonstrated in pancreas by means of an immunoperoxidase technique. They had the same distribution in acinar cells of 'normal' human exocrine pancreas tissues. Ductal adenocarcinoma tissue and pancreatic undifferentiated carcinoma contained neither antigen. Scattered 'normal'-looking cells in the border area between normal and neoplastic tissue of both types of tumor stained positively for trypsinogen and for PSTI.