Study on the expression of cyclooxygenase-2 protein in gastric carcinoma and correlation with P-glycoprotein

Purpose:To investigate the cyclooxygenase-2(COX-2) expression in gastric carcinoma and investigate the effects of COX-2 expression on P-glycoprotein. Methods:The expression of COX-2 and P-glycoprotein was examined by immunohistochemical staining in 48 cases of gastric carcinoma and 10 cases of normal gastric tissues. Results:There was no positive signal of COX-2 detected in normal gastric tissue. The positive expression rate of COX-2 was 60.4 %(29/48) in gastric carcinoma. The expression of COX-2 was correlated with TNM stage and lymph node metastasis (P0.05). We also found that P-glycoprotein expression rate in COX-2 positive expression group was 82.8 %(24/29), and 63.2%(12/19) of P-glycoprotein was not expressed in COX-2 negative expression group. The over-expressions of COX-2 was significantly correlated with P-glycoprotein, The correlation coefficient was r=0.470 (P0.01). Conclusions:COX-2 expression is involved in the carcinogenesis and malignant progression of gastric carcinoma, also COX-2 might take part in mediation of multidrug-resistance (MDR) in gastric carcinoma through interference in the P-glycoprote in expressions.