Quantitative histological changes during early experimental carcinogenesis in the hamster cheek pouch.

Sequential changes in the hamster cheek pouch epithelium following application of the carcinogen dimethyl benzanthracene have been assessed using stereological techniques. The most important progressive change found following cessation of carginogen painting appears to be an increase in the number and size of progenitor cells. Much of the marked increase in stratum corneum thickness seen in the early stages appeared to be related to a hyperplasiogenic rather than a neoplasiogenic action of the carcinogen.