title: Growth, invasion, metastasis, differentiation, angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products.
abstract: OBJECTIVE
  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 113 cases of gastric cancers were studied for the expression of PTEN and Caspase-3 and microvessel 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 % vs 89.4 %; P=0.000, chi(2)=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, chi(2)=7.286). Caspase-3 expression was dependent of PTEN expression in primary gastric cancer cells (P=0.000, chi(2)=15.266).
  
  
  CONCLUSIONS
  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-3 to disorder apoptosis of tumor cells, which might explain the molecular mechanisms of PTEN contributions to tumorigenesis and progression of gastric cancer.
authors.affiliation: Lab. 4, Cancer Institute, The First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China. zheng_huachuan@hotmail.com
authors.forename: Hua-Chuan
authors.initials: HC
authors.lastname: Zheng
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Li
authors.forename: Jin-Min
authors.initials: JM
authors.lastname: Sun
authors.forename: Xue-Fei
authors.initials: XF
authors.lastname: Yang
authors.forename: Xiao-Han
authors.initials: XH
authors.lastname: Li
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Jiang
authors.forename: Yin-Chang
authors.initials: YC
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Xin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000378:metabolism; D013274:Stomach Neoplasms / Q000098:blood supply* / Q000473:pathology* / Q000503:physiopathology / Q000556:secondary; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases