Table 1. Histological changes in rat tongue by 4NQO treatment.
Group (week) |
No. of normal | Mild epithelial dysplasia | Moderate epithelial dysplasia | Severe epithelial dysplasia |
No. of SCC | Incidence (%) |
---|---|---|---|---|---|---|
control | 5 | 0 | 0 | 0 | 0 | 0 |
9week | 0 | 4 | 3 | 0 | 0 | 0 |
13week | 0 | 1 | 5 | 1 | 0 | 0 |
20week | 0 | 0 | 5 | 0 | 0 | 0 |
24week | 0 | 0 | 0 | 2 | 4 | 33.3 |
32week | 0 | 0 | 0 | 0 | 8 | 100 |