[Expression and significance of P-glycoprotein, glutathione S-transferase-pi and Topoisomerase II in gastric carcinomas].

Background & Objective: Multi-drug resistance(MDR) is the most important failing reason of tumor chemotherapy, the substance that P-glycoprotein(P-gp), glutathione S-transferase-pi(GST-pi), Topoisomerase II (Topo II) etc was the fundamental substances producing MDR. Gastric carcinoma is the relatively familiar malignancy, the report was relatively fewness that the expression of P-gp, GST-pi and Topo II by means of immunohistochemistry were associated with in the gastric carcinomas of previously untreated patients. This study was designed to investigate the expression and significance of P-gp, glutathione S-transferase-pi(GST-pi) and Topoisomerase II(Topo II) in gastric carcinomas.

Methods: Seventy-five human gastric carcinomas of previously untreated patients were studied for the expression of P-gp, GST-pi and Topo II by means of immunohistochemistry.

Results: The expression of P-gp, GST-pi and Topo II were 76.0%, 85.3% and 68.0% in gastric carcinoma tissues. There was no significant relationship between the expression levels and age, sex, location of tumor and depth of tumor invasion. Positive rate was higher in glandular-form carcinoma than that in mucoid carcinoma, signet-ring cell carcinoma and poorly differentiated carcinoma (P < 0.05). There was a significant relationship between the lymph node involvement and the higher expression of P-gp, GST-pi, lower expression of Topo II.

Conclusion: There is a correlation between the expression of P-gp, GST-pi, Topo II and histologic subtypes, the expression may also related to the differentiation and metastasis of the gastric carcinomas.