The frequency of spontaneously-occurring neoplasms in the male Syrian golden hamster.

The frequency of spontaneously-occurring neoplasms in the male Syrian golden hamster, often used as a control in carcinogenic studies, was examined. The hamsters were divided into 2 groups: Group 1 received 0.1 ml of the phosphate buffer vehicle intratracheally once a week for 15 w; Group 2 received 0.1 ml of Tween 60:ethanol:buffer (5.3:8.7:100 by volume) in the same manner. The mean survival days of hamsters' total life-span were 574.9 +/- 176.1 d in Group 1 and 427.7 +/- 178.1 d in Group 2. Tumor incidence rates were 10.6% (16/148) in Group 1 and 11.5% (13/113) in Group 2. The mean survival days for tumor-bearing hamsters in Group 1 was 692.0 +/- 80.7 d and was 650.8 +/- 74.2 d in Group 2. Most tumors increased with advancing hamster age. The most common neoplasm was adrenal gland tumors (Group 1 = 4.7%, Group 2 = 8.8%). The occurrence of other tumors in other organs was low. The Syrian golden hamster is a suitable animal model for evaluating chemical carcinogenicity.