Expression of P-glycoprotein, DNA topoisomerase II, glutathione S-transferase π in malignant digestive canal carcinomas

Objective: To observe the expression of P-glycoprotein (P-gp), DNA topoisomerase Ⅱ (Topo Ⅱ ) and glu-tathione S-transferase π (GSTπ) in human malignant digestive canal carcinomas. Methods: Expression of P-gp,Topo Ⅱ and GSTπ in tumor tissues of 47 patients with malignant digestive canal carcinomas were determined by immunohistochemical staining. Results: (1) The positive rates of P-gp expression in esophagus,gastric and colorectal carcinomas were 0,16. 7 Mi and 66. 7% respectively,while those of Topo I were 86. 7% ,91. 7% and 100% ,and those of GSTπ were 20. 0% ,25. 0% and 48. 9%. (2)The expression level of P-gp showed a significant relation with that of GSTπ (r=0. 979,P0. 05). (3) The positive rate of P-gp and GSTπ expression in moderately-differentiated gastric carcinomas showed no statistical difference with that in poorly-differentiated gastric carcinomas .while the positive rate of P-gp expression was significantly higher in well-differentiated colorectal carcinomas than that in moderately-differentiated ones(P0. 05). Conclusion: It suggests that P-gp, Topo Ⅱ and GSTπ play limited roles in multidrug resistance(MDR) phenotype of esophagus and gastric carcinomas, but P-gp is related to the MDR phenotype of colorectal carcinomas.