Expression of cell-cycle regulators Rb,cyclin D1 and CDK4 during carcinogenesis of gastric mucosa

Objective To investigate the significance of the expression of Rb,Cyclin D1 and CDK4 regulator of cell cycle during the carcinogenesis of gastric mucosa.Methods Immunohistochemical staining technique was used to observe Rb,Cyclin D1 and CDK4 regulators of cell cycle expression in 50 cases of gastric carcinoma,of which 18 intestinal metaplasia(IM),7 mild/moderate atypical dysplasia(Dys) and 9 severe Dys(mucosa adjacent to the tumor).Results Rb over expression was found in mild/middle Dys,severe Dys and gastric carcinoma.The increasing frequency of immunoactivity was found in the gastric carcinoma compared with severe Dys( P 0.05),cyclin D1 and CDK4 protain was found only in gastric cancer.Thirteen of Cyclin D1 positive gastric cancer showed five cases of CDK4 positive and two cases of Rb simultaneity.Seventeen of Rb positive gastric cancinoma showed 3 cases of CDK4 positive simultaneity.Conclusions Overexpression of Rb,Cyclin D1 and CDK4 may involve in the onco pathogenesis of gastric carcinoma.Overexpression of Rb was characteristic of the early phase of gastric carcinogenesis.Cyclin D1 and CDK4 were a late event in gastric carcinogenesis.