ABSTRACT
<p><b>OBJECTIVE</b>To study the expression and significance of apoptosis-related protein p53, Bcl-2, and Bax during the development of oral squamous cell carcinoma (SCC).</p><p><b>METHODS</b>The expression was observed in 10 normal oral epithelia, 48 dysplasia epithelia and 42 SCC by immunohistochemical evaluation.</p><p><b>RESULTS</b>In normal mucosa, the positive rate of p53, Bcl-2 and Bax were 0%, 20% and 60%. In dysplasia epithelia, the positive rate of p53 is increased (P < 0.05), the positive rate of Bcl-2 and Bax remained no significant change (P > 0.05), but the positive intensity in severe dysplasia was higher than in mild group. In SCC, the positive rate of Bcl-2 increased significantly (compared with dysplasia, P < 0.05), while the expression of Bax was decreased with the increase of SCC histological grade. Further analysis showed the correlation was evident in p53 and Bax in dysplasia, and in p53 and Bcl-2 in SCC.</p><p><b>CONCLUSIONS</b>In dysplasia, p53 gene mutation results in accumulation of dysplasia cells. In SCC, the cooperation of p53, Bcl-2 and Bax results in the progression of SCC. Apoptosis genes could work either independently or cooperatively.</p>