ABSTRACT
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.