中文摘要：

目的：研究口腔黏膜异常增生不同阶段上皮细胞E-cadherin及Twist1启动子甲基化,探讨其意义。方法：使用量子点免疫荧光技术检测口腔黏膜异常增生中Twist1的表达。随机选取口腔黏膜上皮异常增生组织,使用甲基化特异性PCR检测其甲基化状态,分别以口腔黏膜单纯过度角化,口腔鳞癌细胞系及口腔鳞癌组织作为阴性或阳性对照。结果：Twist1在口腔黏膜单纯过度角化中几乎不表达,在口腔异常增生黏膜中随上皮异常增生程度加重而升高（P〈0.05）。在轻、中、重度的口腔黏膜异常增生的样本中,Twist1甲基化率随上皮异常增生程度加重而升高,分别为15.8%,29.4%,50%,差异有显著性（P〈0.05）。口腔癌组织Twist1甲基化率为62.5%,口腔癌细胞系为60%,而单纯过度角化中Twist1未出现甲基化;与异常增生相比具有统计学意义（P〈0.05）。在不同程度的异常增生上皮中,E-cadherin甲基化率分别为33.3%,50%,62.5%,未显示统计学差异。Twist1和Ecadherin的甲基化率无明显相关性（P〉0.05）。结论：Twist1启动子甲基化可能发生在黏膜异常增生早期阶段,且与口腔黏膜上皮癌变过程关系密切。

英文摘要：

Objective：To investigate the promoter methylation status of E-cadherin and Twistl in differ- ent grades of oral epithelial dysplasia （OED） and discuss the significance. Methods： The expres- sion of Twistl was detected in different grades of OED by quantum dot simmunofluoreseence his- tochemistry （QDs-IHC）. OED tissue samples were randomly selected from the department of O- ral Pathology, Hospital of Stomatology of Wuhan University, which were dial：nosed by pathologists. Oral epithelium hyperkeratosis and oral squamous cell carcinomas （OSCC） cell lines to- gether with oral carcinoma tissue samples were used as positive or negative control respectively. Methylation Special PCR （MSP） was performed to detect the methylation status of E-cadherin and Twist1 promoter. Statistical analysis was performed to explore the correlation of methylation status between E-cadherin and Twistl by using SPSS 17.0 Statistic software. Results. The ex- pression of Twist1 increased progressively in different grades of OED but was not expressed in o- ral epithelium hyperkeratosis. The methylation rate of Twistl significantly increased with the ag- gravated grade of OED, that was 15.8%, 29.4% and 50% ,respectively （P〈0.05）. The methyl- ation rate of Twist1 in OSCC tissue sample and cell lines were 62. 5% and 6%, respectively, which was not detected in oral epithelium hyperkeratosis. The difference of Twistl methylation rate between OED and positive/negative control was remarkable （P〈0.05）. The methylation rate of E-cadherin was 33.3% ,50% and 62.5% in mild, moderate and severe OED, whereas, the