Hamster tongue carcinogenesis II. Quantitative morphologic aspects of preneoplastic epithelium.

Stereological techniques have been used to quantify some morphologic aspects of non-neoplastic and preneoplastic hyperplasia in hamster tongue. Scratching hamster ventral lingual mucosa and applying acetone thrice weekly resulted in moderate epithelial hyperplasia in biopsy material removed at 16 weeks. There was a significant increase in the number of progenitor cells per defined histologic field and a striking increase in the number of progenitor cells related to each unit of surface length. There was a small but significant increase in basement membrane length. In the experimental group in which the ventral lingual mucosa was scratched and painted with 0.5% DMBA in acetone there was pronounced epithelial hyperplasia with increases in the thickness of the progenitor, maturation and keratinized compartments. Progenitor cells showed hyperplasia and hypertrophy. The number of progenitor cells related to each unit of surface length was significantly greater than normal or control values. There was a significant increase in the basement membrane length per field, reflecting an increased folding and prominence of the rete ridges.