Chemical Carcinogenesis in the Hamster Submaxillary Gland

¹ Department of Oral Pathology, Tufts University, School of Dental Medicine, Boston, Massachusetts

A simple and uniform method for the formation and implantation of pellets of powdered chemical carcinogen in the submaxillary salivary gland of experimental animals has been described. The submaxillary salivary glands of thirty-four male and female Syrian hamsters were implanted with 5 mg. pellets of powdered 9,10-dimethyl-1,2-benzanthracene. Groups of 4 animals were sacrificed at 4, 6, 8, 10, 12, and 14 weeks. The 10 remaining animals were sacrificed at 8 months. Sixteen animals served as controls.

Extremely large tumors were grossly visualized at the 8-month interval of sacrifice. Varieties of microscopic alterations were noted including epithelial hyperplasia and metaplasia, connective-tissue hyperplasia, and areas resembling a mixed tumor pattern; however, the only tumors produced were fibrosarcomas. It was suggested that in the salivary glands of experimental animals, although numerous tissue responses may occur, only one tissue usually undergoes neoplastic transformation. In the hamster the connective tissue apparently plays this role.