Cell kinetic study on experimental tongue carcinoma in rats.

Tongue carcinomas were produced in rats by oral administration of 0.001% 4-nitroquinoline 1-oxide (4NQO) in drinking water, and the biological characteristics and tumor kinetics were correlated. Bromodeoxyuridine (BrdU) was used to investigate cell kinetics of rat tongue tumors in vivo. BrdU-labeled S-phase cells were demonstrated by an indirect peroxidase method using anti-BrdU monoclonal antibody, and their percentage, the labeling index (L.I.), was determined. The average BrdU L.I. in normal tongue epithelium, well differentiated and moderately differentiated squamous cell carcinoma was 5.7 +/- 1.1, 8.8 +/- 3.7 and 14.9 +/- 5.4, respectively. The differences among the three groups are significant. These results indicate that the BrdU L.I. correlates well with the degree of differentiation of tongue epithelium. Furthermore, the distribution patterns of BrdU-labeled cells in the tissue sections of each group were different. If these cell kinetics studies using BrdU are applied to human tongue carcinomas, the data may provide information on the biological characteristics and help in establishing the diagnosis and in choosing treatment regimens.