Analysis of proliferating potential by argyrophilic nucleolar organizer regions (AgNORs) and proliferating cell nuclear antigen (PCNA) staining in experimental pancreatic ductal carcinoma in dogs.

-Study of the incipient phase of pancreatic ductal carcinoma-

Abstract

Proliferating potential of the incipient phase of pancreatic ductal carcinoma in 9 dogs were studied by AgNORs and PCNA staining. Various pancreatic lesions including intraductal carcinoma, dysplasia and papillary hyperplasia, were found more fregvently in the intraductal administration group than in the group receiving a total dose of 350mg N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG). However, only hyperplasia was found less often in the intraductal administration group compared to that in the group receiving a total dose of 130mg ENNG. There were significant differences between the two group. AgNORs score and RCNA positive rate increased as the degree of atypia increased. AgNORs score and PCNA positive rate increased in a stepwise manner in pancreatic ductal lesions during the process of pancreatic ductal carcinogenesis. There were significant differences between two processes. The AgNORs score correlated well with the PCNA positive rate. The results suggested that dysplasia is important during incipient phase of experimental pancreatic ductal carcinoma in dogs.