Spontaneous Tumors and Common Diseases in Two Colonies of Syrian Hamsters. I. Incidence and Sites2

Abstract
Syrian hamsters from two colonies [Eppley colony (EC); Hannover colony (HC)] were examined for spontaneous neoplastic and nonneoplastic diseases. Significant differences were found in tumor incidence (30%, EC; 42%, HC), occurrence of malignant neoplasms (15%, EC; 32%, HC), appearance of multiple primary tumors in different organs (42%, EC; 30%, HC), average survival rates of tumor-bearing animals, organ distribution and histologic types, and average survival rates of all animals. The frequencies of nonneoplastic diseases also varied between the two colonies. The findings indicated a need for precise histologic evaluation to generate information for comparative purposes regarding the use of hamsters in experimental pathology and carcinogenesis studies.