Growth,invasion,metastasis,differentiation,angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products

摘要

AIM: To investigate expression of PTEN in gastric cancer and to explore its roles in tumorigenesis and progression of gastric cancer.METHODS: Formalin-fixed and paraffin-embedded tissues of adjacent non-tumor mucosa and primary foci from 113cases of gastric cancers were studied for the expression of PTEN and Caspase-3 andmicrovessel density (MVD)by streptavidin-peroxidase (S-P) immunohistochemistry with antibodies against PTEN, Caspase-3, and CD34. The relationship between PTEN and Caspase 3 expression and clinicopathological parameters of tumors was compared.RESULTS: Primary gastric cancer cells expressed PTEN less frequently than adjacent epithelial cells of primary foci (54.9％ vs89.4％; P=0.000, χ2=33.474). PTEN expression was significantly associated with invasive depth (P=0.003,rs=0.274), metastasis (P=0.036, rs=0.197), growth pattern (P=0.008, rs=0.282), Lauren′s classification (P=0.000,rs=0.345), and histological classification (P=0.005, rs=0.262)of tumors, but not with tumor size (P=0.639, rs=0.045),Borrmann′s classification (P=0.544, rs=0.070) or TNM staging (P=0.172, rs=0.129). PTEN expression was negatively correlated with MDV in primary gastric cancer (P=0.020,F=5.558). Primary gastric cancer cells showed less frequent immunoreactivity to Caspase-3 than adjacent epithelial cells of primary foci (32.7 ％ vs 50.4 ％; P=0.007,χ2=7.286).Caspase-3 expression was dependent of PTEN expression in primary gastric cancer cells (P=0.000, χ2=15.266).CONCLUSION: Down-regulated expression of PTEN plays an important role in tumorigenesis, progression, growth,differentiation and angiogenesis of gastric cancer. Low expression of PTEN can decrease expression of Caspase-3to disorder apoptosis of tumor cells, which might explain the molecular mechanisms of PTEN contributions to tumorigenesis and progression of gastric cancer.