Characterization of the ELSV transgenic mouse model of pancreatic carcinoma. Histologic type of large and small tumors.

Carcinomas of the pancreas that developed in Tg(Ela-1, SV40E)Bri18 and Tg(Ela-1, SV40E+Ela-1, neo)Bri19 strains of transgenic mice were classified into eight histologic patterns. Most were variants of acinar cell carcinoma, but cystic and undifferentiated carcinomas were found. The spectrum of phenotypes was similar in small and large carcinomas, but the small group included a higher fraction of well-differentiated tumors and fewer poorly differentiated and anaplastic tumors. The incidence of islet cell tumors was far higher in the Bri18 strain (77%) than in the Bri19 strain (1.6%). Islet cell hyperplasia was much more prevalent in Bri18 than Bri19 mice. In both strains, the nontumorous pancreas showed acinar cell dysplasia with a more abnormal and distinctive pattern in the Bri19 strain. While the spectrum of exocrine tumor phenotypes is similar, significant differences occurred between these two transgenic mouse strains as models for pancreatic carcinogenesis.