Rapid induction of subcutaneous fibrosarcoma by 7,12-dimethyl-benz(a)anthracene in an inbred line of Syrian hamsters.

Single s.c. injections of 500 ^g 7,12-dimethylbenz(a)anthracene in tricaprylin were given to 25 males and 25 females of 10 inbred strains of Syrian hamsters. In 9 strains, the average time of latency before palpable tu mors appeared was 13 to 16 weeks. In 1 strain, BIO 15.16, the average latency was 10 weeks. These differ ences are statistically significant. In this line, the first palpable tumors appeared in both sexes 5 weeks follow ing carcinogen injection. All animals of this line devel oped tumors within 15 weeks after carcinogen injection [there was a single exception in a male (included in the average latency) wherein a tumor developed 34 weeks after injection]. Histologically, the tumors were fibrosarcomas invading the subcutaneous musculature and morphologically indistinguishable from similarly induced tumors in other strains. There were few métastases;all tumors tested grew upon subcutaneous transplantation into hamsters of the same as well as of unrelated strains.