Spontaneous tumors in the Campbell hamster: A possible new model of experimental oncology

Abstract

The spectrum of spontaneous tumors in the Campbell hamsters has not been described yet. 152 Campbell hamsters (110 females and 42 males), spontaneously died by ordinary death, underwent the necropsy and the histopathological examination. Tumors were found in 50% of males and in 48% of females dead after the achievement of the first tumor development age (430 and 260 days respectively). The main type of tumors in Campbell hamsters was thymoma of B1 type which is known in human, but unusual in laboratory animals. The thymomas had low grade of malignancy, did not induce the wasting syndrome and did not metastasize. It is probable that thymoma B1 kills the animals by the dislocation of mediastinal organs. Frequency of this tumor was 40% in males and 40% in females dead after the achievement of the first tumor development age. Any sex differences were not found although males dead with thymoma had significantly more evident reproductive success in comparison with animals without this tumor. Besides, thymomas, squamous carcinomas of forestomach (in males and females), skin carcinomas (in males and females), adenocarcinomas of reproductive system, kidney and lung (in females only) and small-cell lymphomas (in males only) were found. Hence, spontaneous tumors in Campbell hamsters could be useful as a model for research in the experimental oncology, especially as unique model of human thymoma of B1 type which has not been observed in laboratory mice and rats yet.