[The expression of multiple drug resistance associated genes in ovarian cancer]

The aim of the investigation was to find out the relationship between the expression of multidrug resistance gene (MDR1), multidrug resistance protein (MRP), lung resistance protein (LRP) and glutathione S-transferase pi (GST-pi) with the clinical pathological characteristics and the prognosis in the ovarian cancer patients who never received chemotherapy before operation.

The expression of MDR1, MRP, LRP and GST-pi in 41 cases of ovarian cancer, 25 cases of benign ovarian tumor and 12 normal ovary tissue were investigated by reverse transcription-polymerase chain reaction (RT-PCR).

In normal ovary, benign tumor and ovarian cancer, the positive expression of MDR1 was 0.0%, 0.0% and 29.3%, the positive of MRP was 16.7%, 12.0% and 53.7%, the positive of LRP was 25.0%, 52.0% and 87.8%, the positive of GST-pi was 8.3%, 12.0% and 51.2% respectively. The ratios of co-expression of multiple genes in ovarian cancer were much higher than that in benign ovarian tumor. All tested genes showed no significant relationship to the clinical stage, histological type and the differentiation of the tumor except that the expression of MDR1 and MRP was closely related to the differentiation (P < 0.05). The non-responders to platinum or taxol based combination chemotherapy exhibited higher ratios of MDR1 and MRP expression than the responders (P < 0.05). Furthermore, the co-expression phenomenon was more common in non-responders.

Multiple gene expression is involved in drug resistance in ovarian cancer. The co-expression of MDR1, MRP, LRP and GST-pi is higher in ovarian cancer than that in benign ovarian tumor and normal ovary tissue. The expression of MDR1 and MRP is closely related to the tumor differentiation and the response to chemotherapy.