Vascularization of premalignant lesions in carcinogen-treated hamster cheek pouch.

Of 27 lesions induced in Syrian golden hamsters by 12 applications of 0.5% 7,12-dimethylbenz[a]anthracene in liquid paraffin, 14 showed a static phase of at least 28 days' duration in their life history. Ten static lesions resumed growth, and this was accompanied by clinically obvious vascularization in 8 cases, 7 of which culminated in carcinomas by the end of the study. Because the wall of the normal hamster cheek pouch possesses small nodules whose histologic structure closely resembles that of hyperplastic epithelium, they could be misinterpreted as a product of carcinogenesis.