Apoptosis in the process of carcinogenesis of oral precancerous lesions

应用免疫组化方法检测了口腔白斑、白斑癌变及口腔鳞癌组织中刘易斯^y（le^y）抗原、TGF-α、P53蛋白、bcl-2蛋白及PCNA的表达。此外，通过使用Tunel方法检测DNA片段化来研究这些标本中细胞凋亡的发生。此外，我们在体外研究是否可以诱导口腔上皮细胞凋亡的抗癌药物和硝普钠（SNP）。结果表明：1.口腔癌组织中Le ^y抗原和bcl-2蛋白的表达较白斑组织弱; 2.在口腔粘膜白斑中，Le^y抗原和bcl-2蛋白的表达随上皮异型增生程度的加重而降低，而TGF-α、P53蛋白和PCNA的表达则随上皮异型增生程度的加重而降低。P53蛋白和PCNA表达随上皮不典型增生程度的增加而增加。Tunel法检测到口腔黏膜白斑中DNA片段化发生率高于口腔癌，5-Fu、顺铂和SNP均可诱导口腔黏膜上皮细胞（NA）凋亡，c-myc、c-myb、p53 mRNA表达在凋亡过程中下调。

We investigated the expression of lewis^y (le^y) antigen, TGF-alpha, P53 protein, bcl-2 protein and PCNA immunohistochemically in the specimens which were obtained from patients with leukoplakia, cancer developed from leukoplakia and oral squamous cell carcinoma. Further, occurrence of apoptosis in those specimens was studied by detecting the fragmentation of DNA using Tunel method. In addition, we examined in vitro whether apoptosis could be induced in oral epithelial cells by anticancer drugs and sodium nitroprusside (SNP). We also examined the changes in the expression of genes during apoptosis.The results obtained were as follows :1.Le^y antigen and bcl-2 protein in oral cancer were expressed more weakly than those in leukoplakia. On the contrary, TGF-alpha, P53 protein and PCNA in oral cancer were expressed more strongly than those in leukoplakia.2.The expression of Le^y antigen and bcl-2 protein decreased with the grade of epithelial dysplasia in leukoplakia, whereas the expression of TGF-alpha, P53 protein and PCNA increased with the grade of epithelial dysplasia.3.The expression of Le^y antigen and bcl-2 protein decreased with malignant transformation.4.DNA fragmentation detected by Tunel method occurred more frequently in leukoplakia than in oral cancer.5-Fu, cisplatin and SNP could induced apoptosis in oral epithelial cells (NA) and mRNA expression of c-myc, c-myb, p53 was downregulated during apoptosis.