Objective   This work aimed to evaluate the expressions of E-cadherin and cyclooxygen ase-2(COX-2) in primary gastric carcinoma and adjacent mucosa, and to investigate the correlation between abnormal expression of the said proteins and the clinico-pathological features of gastric adenocarcinoma.

  Methods   Immunohistochemical staining was used to determine the expression of E-cadherin and COX-2 on tissue microarray slices obtained from gastric carcinoma and adjacent mucosa of over 100 cases from the Cancer Institute and Hospital of Chinese Academy of Medical Science between February 2005 and October 2006.

  Results   The positive expressions of E-cadherin and COX-2 were 76.9%(93/121) and 38.1%(45/118), respectively, in gastric carcinoma, whereas E-cadherin expression was 100% in 113 cases with adjacent mucosa.The positive expression of E-cadherin was significantly correlated with clinical characteristics such as gross type(P=0.014), differentiation(P=0.004), and pTNM stage(P=0.024).COX-2 expression was higher in gastric cancer cases with lymph node me tastasis than those without, and the result was significantly different(P=0.048).

  Conclusion   E-cadherin is a tumor-inhibiting factor and COX-2 is a carcinogen.Positive expression of E-cadherin and negative expression of COX-2 are correlated with better prognosis.E-cadherin and COX-2 may thus be used as potential markers of tumor progression and prognosis.