The Expressionof PTEN And MDM2 In Gastric Carcinoma And Itscorrelation

Objective:To detect the expression of PTEN and MDM2 in normal gastric tissue,atypical hyperplasia tissues and gastric carcinomaby immunohistochemistry S-P method andinvestigate the role of PTEN and MDM2 in the development of gastric carcinoma, Providing new molecular biological indicatorsfor early diagnosis and clinical treatment of gastric cancer.Methods: 100 cases of experimental samples were taken from archive paraffin blocks of pathology department, the Affiliated Hospital of Sichuan Medical University from January 2013 to June 2014.Including20 cases of normal gastric mucosa(away from the tumor cutting margin of 5cm), 18 cases of atypical hyperplasia tissues(9 cases of mild atypical hyperplasia, 9 cases of severe atypical hyperplasia),62 cases of gastric carcinoma. The histological type of each specimen was diagnosised by two experienced pathologist.Immunohistochemistry S-Pmethod was used to detect the expression of PTEN and MDM2 in each group and the relationship between PTEN and MDM2 in various lesions of the gastric mucosa, as well as the correlation with clinical pathological characteristics of gastric cancer were analyzed.SPSS(19.0 version) statistical software was used for statistical analysis, count data using chi-square test,correlation analysis using Spearman rank correlation analysis, P<0. 05 was considered statistically significant.Results:(1)In gastric cancer tissues, the positive expression rate of PTEN was 32.26%(20/62),in atypical hyperplasia tissues the positive expression rate of PTEN was 61.11%(11/18),and in normal gastric mucosa the positive expression rate of PTEN was 95%(19/20);The differences between gastric cancer tissues and atypical hyperplasia group, normal gastric mucosa tissues(x2=4.89,p<0.05; x2=21.42, p<0.05) were statistically significance;In normal gastric mucosa tissues,the positive expression rate of PTEN was significantly higher than that in atypical hyperplasia tissues and the difference was statistically significant(x2=4.67,p<0.05). In gastric cancer tissues, the positive expression rate of MDM2 was 62.90%(42/62),in atypical hyperplasia tissues the positive expression rate of MDM2 was 44.44%(8/18),and in normal gastric mucosa the positive expression rate of MDM2 was 10%(2/20);The differences between gastric cancer tissues and atypical hyperplasia, group normal gastric mucosa tissues(x2=4.31,p<0.05;x2=20.42,p<0.05) were statistically significance;In atypical hyperplasia tissues, the positive expression rate of MDM2 was significantly higher than that in normal gastric mucosa and the difference was statistically significant(x2=4.16,p<0.05).⑵The positive expression of PTEN had no significant relationship with age, gender and tumor size of gastric carcinoma(p>0.05),but the expression of PTEN was closely related to the depth of invasion of gastric wall, lymph node metastasis, and TNM stage(P <0.05); the expression of MDM2 was closely related to the depth of invasion of gastric wall, lymph node metastasisand TNM stage(P <0.05),but the positive expression of MDM2 had no significant relationship with age, gender and tumor size of gastric carcinoma(p>0.05);(3)Expression of the PTEN and MDM2 in gastric carcinoma was negatively correlated through the correlation analysis(r=-0.623,P<0.05). Conclusions:1. The positive rates of the expression of PTEN in normal gastric tissue、atypical hyperplasia tissues and gastric carcinoma were low in turn,the positive rates of the expression of MDM2 in normal gastric tissue、atypical hyperplasia tissues and gastric carcinomawere high in turn,detectingthat both PTEN and MDM2 participate in theoccurrence and development of gastric cancer. 2.The expression of PTEN and MDM2 were closely related to the depth of invasion, degree of differentiation,lymph node metastasis, and TNM stage,it detected that the expression of PTEN and MDM2 can be used as one of the indicators in prognosis of gastric cancer. 3.The weak expression of PTEN ingastric cancer tissues has certain relationship with the over-expression of MDM2, speculating that the pathway of PTEN—PI3K—AKT/PKB—MDM2一P53/PRb/E2 Fplays a certain rolein the occurrence,development and metastasis process of gastric carcinoma.