Evolution of the expression of fetal acinar antigens during carcinogenesis of the pancreas in hamsters: individual follow-up by open biopsy.

Individual lesions in the pancreas and the presence of fetal acinar antigens along with carcinogenesis induced by N-nitrosobis(2-oxopropyl)amine (CAS: 60599-38-4) were studied by open biopsy in 16 Syrian golden hamsters 13, 22, and 40 weeks after initiation of treatment. At 13 weeks, cystadenoma and regular ductal hyperplasia were noted in 3 animals and 1 animal, respectively. Staining for fetal acinar antigens in the pancreas was found in 69% of the hamsters. At 22 weeks, cystadenoma and hyperplastic ducts were common (60 and 53%), and 3 hamsters developed pancreatic adenocarcinoma. Fetal acinar antigens persisted in the acini and extended to irregular hyperplastic ducts and tumor cells. At 40 weeks, ductal proliferation was the main lesion in all pancreatic tissue, and 9 animals had adenocarcinoma. Acinar antigens were found in the remaining acini, in irregular hyperplastic ducts, and in tumor cells. Thus, once reexpressed, fetal acinar antigens persist in pancreatic lesions and pancreatic carcinomas in the hamster.