E-cadherin在胃癌侵袭转移中的作用及对预后的影响

目的：从DNA、RNA和蛋白水平分析胃癌中E-cadherin（ E-cad）表达，旨在探讨E-cad在胃癌侵袭转移中的作用及对预后的影响。方法分别应用免疫组化SP法及原位杂交检测60例胃癌组织和癌旁组织中的E-cad蛋白表达及E-cad mRNA表达；同时应用MSP法检测E-cad DNA甲基化水平。结果 E-cad mRNA和 E-cad蛋白在胃癌中的阳性表达显著低于癌旁组织，E-cad DNA甲基化在胃癌阳性表达率高于癌旁组织。E-cad DNA甲基化与E-cad蛋白、E-cad mRNA在胃癌中的表达缺失呈负相关性（r＝-0.335，r＝-0.271），E-cad基因甲基化与胃癌5年生存率成负相关（r ＝-0.381，P﹤0.01）。E-cad蛋白表达与胃癌5年生存率成正相关，（r＝0.378，P﹤0.01）。结论 E-cad低表达是胃癌的重要生物学特征，而E-cad甲基化可能是导致胃癌E-cad mRNA和E-cad蛋白低表达的重要原因，E-cad甲基化水平可以作为预测胃癌侵袭转移及预后的重要指标。

Role and prognostic impact of E-cadherin expression on invasion and metastasis of gastric carcino-ma

Objective To investigate the role and prognostic impact of E-cadherin（ E-cad）on in-vasion and metastasis of gastric carcinoma by analyzing E-cadherin expression at DNA,RNA and protein levels. Methods RNA and protein expression of E-cad were tested in 60 cases of gastric carcinoma and adjacent tissues by streptavidin peroxidase（ SP ）immunohistochemistry and in situ hybridization. DNA methylation of E-cad was tested with methylation-specific polymerase chain reaction（ MSP）. Results The positive rates of E-cadherin protein and mRNA in gastric carcinoma were significantly lower than those in adjacent tissues. DNA methylation of E-cad negatively correlated with the E-cad protein and RNA expres-sion in gastric carcinoma respectively（r= -0. 355,r = -0. 271）. DNA methylation of E-cad negatively correlated with the 5-year survival rate of gastric carcinoma（r = -0. 381,P ﹤0. 01）. However,E-cad protein positively correlated with the 5-year survival rate of gastric carcinoma（r=0. 378,P﹤0. 01）. Con-clusion The decreased expression of E-cad is one of the most important biological features in gastric car-cinoma. Methylation of E-cad DNA may be an important agent causing low expression of E-cad protein and mRNA and it can be used as an important indicator in predicting invasion and metastasis of gastric cancer.