[Expression of p53 and Ki-67 genes in epithelial dysplasia from old oral mucosa and clinical significance].

OBJECTIVE: To elucidate the relationship between the malignant transformation of oral epithelial dysplasia and the expression of p53 and Ki-67 proteins. METHODS: The expression of p53 and Ki-67 proteins from 60 cases of oral epithelial dysplasia (28 cases of mild epithelial dysplasia, 32 cases of severe epithelial dysplasia) and 30 normal oral mucosa tissue was determined by immunihistochemistry, and a 5-year follow-up study was made. RESULTS: In normal epithelium, Ki-67 expression was only observed in a small number of cells, and no expression of p53 was detected. In the cases of mild epithelial dysplasia, low levels of Ki-67 and p53 expression were detected. In the cases of severe epithelial dysplasia, the expression of p53 and Ki-67 protein was significantly higher than that in the normal oral mucosa and in the mild epithelial cases (P < 0.05). There was a correlation between the malignant transformation and the mutation of p53, Ki-67 in the cases of oral epithelial dysplasia. CONCLUSION: Carcinogenesis of oral mucosa is a continuous and stepwise course; p53 and Ki-67 genes may play an important role in this course.