Cell cycle and apoptosis in the process of carcinogenesis in oral precancerous lesions

检测口腔白斑（OLP）和口腔癌组织中G1细胞周期蛋白、细胞周期蛋白依赖激酶（CDK）和p21/waf1的表达。此外，我们还研究了p53基因敲除小鼠口腔黏膜角质形成细胞的生长活性和细胞周期。实验结果如下：1。Cyclin D1、Cyclin E、CDK2和CDK4在正常口腔黏膜上皮中每周均有表达，而在OLP中随着上皮发育不良程度的增加表达增强。中度和重度上皮发育不良的OLP和口腔癌组织中各阳性均显著高于正常口腔粘膜上皮组织2。p21/waf1在正常口腔黏膜上皮和口腔癌组织中不表达，但在中度和重度上皮发育不良的OLP中发现。而p21/waf1 mRNA在所有组织中均有表达。tunel阳性细胞多见于正常口腔黏膜上皮。随着上皮发育不良程度和癌变程度的增加，tunel阳性细胞率呈下降趋势。p53基因敲除小鼠口腔黏膜角质形成细胞的生长活性高于正常（野生）小鼠。流式细胞术分析显示，p53敲除小鼠G1期持续时间缩短。这些结果提示细胞周期紊乱和细胞凋亡抑制可能与OLP的癌变有关。

Expression of G1 cyclins, cyclin dependent kinases (CDK) and p21/waf1 was examined in oral leukoplakia (OLP) snd oral cancer tissue. In addition, growth activity and cell cycle of oral mucosal keratinocytes in p53 gene knockout mouse were also studied.The results obtained were as follows :1.Cyclin D1, cyclin E,CDK2 and CDK4 were weekly expressed in normal oral mucosal epithelium, whereas their expression in OLP became strong with the grade of epithelial dysplasia. Each positivity was significantly higher in OLP with moderate and severe epithelial dysplasia and oral cancer tissues than in normal oral mucosal epithelium.2.p21/waf1 was not expressed in normal oral mucosal epithelium and oral cancer tissue, but it was found in OLP with moderate and severe epithelial dysplasia. However, p21/waf1 mRNA was expressed in all tissues.3.TUNEL-positive cells were most frequently observed in normal oral mucosal epithelium. Decreasing tendency in TUNEL-positive cell rate was found with the grade of epithelial dysplasia and carcinogenesis.4.Growth activity of oral mucosal keratinocytes in p53 knockout mouse was higher than that in normal (wild) mouse. The flowcytometric analysis revealed that the duration of G1 phase was shortened in p53 knockout mouse.These results suggest that the misrule of cell cycle and suppression of apoptosis may be concerned in carcinogenesis of OLP.