Hamster tongue carcinogenesis. I. Characteristics of the experimental model.

Thrice weekly applications of DMBA to hamster ventral lingual mucosa, preceded by scratching with a barbed broach, led to tumor development in over 75% of the animals by 28 weeks. Macroscopic ulceration did not appear to be a necessary precursor of epithelial malignancy in this model. Tumors were preceded by a phase resembling human leukoplakia. In addition to developing tumors in the treated area, 60% of the hamsters developed tumors in the floor of the mouth or the area of mucosa on either side of the median lingual frenum.