title: [Expression of cyclooxygenase-2, hMLH1 and hMSH2 proteins, and their relationship with microsatellite instability in gastric carcinoma].
abstract: OBJECTIVE
  To investigate the expression of cyclooxygenase-2 (COX-2), human mut-l homologue 1 (hMLH1) and human mut-s homologue 2 (hMSH2) proteins in human paired gastric carcinoma (GC) and adjacent normal mucosa, and analyze their relationship with microsatellite instability (MSI).
  
  
  METHODS
  The protein expressions were examined by western blotting. Five MSI loci were assessed by PCR.
  
  
  RESULTS
  In 30 surgically excised GC tissues, the overexpression rate of COX-2, the low expression rate of hMLH1 and hMSH2 were 66.7%, 40% and 33.3%, respectively. Significant differences were found when compared with those of adjacent normal mucosa (P < 0.05). MSI was detected in 13 GC. The number of MSI-H (MSI-High, > or = 2 loci), MSI-L (MSI-Low, only one locus), and MSS (microsatellite stable) were 9, 4 and 17, respectively. The number of low expression rates of COX-2, hMLH1 and hMSH2 in MSI-H were 6, 8 and 5, respectively. There were significant differences compared to that of MSS (P < 0.05).
  
  
  CONCLUSIONS
  The results suggest that microsatellite instability pathway is probably involved in the carcinogenesis of gastric carcinoma, which is frequently accompanied by low expression of hMLH1 and hMSH2, and may be also by low expression of COX-2.
authors.affiliation: Department of Gastrointestinal Surgery, Second Affiliated Hospital, Hebei Medical University, Shijiazhuang 050000, China.
authors.forename: Wei-qing
authors.initials: WQ
authors.lastname: Song
authors.forename: Cai-li
authors.initials: CL
authors.lastname: Han
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Yi-hua
authors.initials: YH
authors.lastname: Zhang
authors.forename: Jin-ying
authors.initials: JY
authors.lastname: Wei
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis* / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics*; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C088996:PMS1 protein, human; D051546:Cyclooxygenase 2; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins