Negative feedback regulation of Cyclin G on the p53-Mdm2 in gastric cancer tissue

Objective To investigate the function of Cyclin G in the p53-Mdm2 negative feed- back loop in gastric cancer tissue and their possible correlation.Methods The SP immunohistochemical staining technique was applied to detect the expression of Cyclin G,Mdm2 and p53 in clinical gastric car- cinoma specimens of 48 cases and the corresponding para-carcinoma gastric tissues.Results Overexpres- sion of Cyclin G protein was detected in nucleus of gastric cancer.The positive rate of Cyclin G,Mdm2 and p53 in gastric carcinoma was 64.6%,47.9 % and 29.1% respectively,significantly higher than that in the corresponding para-carcinoma gastric tissues(P＜0.05 ).There was a positive correlation between Cyclin G and Mdm2 protein(Kappa=0.506),while a negative correlation between the expression of Cy- clin G and p53.No correlation was found between the Cyclin G expression and the Borrmann classification or the grade of tumor differentiation(P＞0.05).Conclusion The abnormal expression of Cyclin G, Mdm2 and p53 may be involved in the pathogenesis and development of gastric carcinoma.Cyclin G can be used as a target of gene therapy for gastric cancer by regulating p53 and its pathway via Mdm2.