Expression And Clinicopathological Significance Of MicroRNA-21 And PTEN In Gastric Carcinoma

MicroRNAs are a class of single-stranded endogenous noncoding small RNAs, 20 to 25 nucleotides in length ,which inhibits mRNA translation or directly degradate the target mRNA through its completely or not completely bonding to 3'-UTR.They produce post-transcriptional gene silencing, regulate gene expression, and play an important role in the proliferation, differentiation, apoptosis, gene regulation of cells and tumorigenesis. Research shows that, miR-21 plays an important role in development of tumors. PTEN gene is found so far the first tumor suppressor with phosphatase, whose mutation or deletion is closely related to many cancers.In this study, 65 cases surgically resected gastric cancer were collected , include gastric cancer tissue and corresponding normal gastric epithelial tissues from September 2007 to March 2010 in the first affiliated hosipital of Xiamen University. Real-time quantitative PCR was used to detect expression of miR-21 and immunohistochemical staining to detect expression of PTEN protein in the gastric cancer and corresponding gastric epithelial tissues. The relationship between the expression of miR-21 or PTEN and clinical pathologic parameters in the gastric cancer was analysed.Results shows that expression of miR-21 was significantly higher in gastric cancer tissues than in corresponding epithelial tissues, it is related to tumor differentiation as well. The poorer differentiation, the higher miR-21 expression . PTEN proteins are located in the nucleus. Expression of PTEN protein is significantly higher in normal gastric epithelial tissues than in gastric cancer tissues; It is significantly higher in diffuse-type gastric cancer than intestinal type accoding to Lauren classification; The higher the pTNM staging, the less the expression of PTEN in gastric cancer tissues. There was no statistically significant relationship between miR-21 and PTEN proteins in gastric cancer.