Multidrug resistance-associated biomarkers PGP, GST-π, Topo-II and LRP as prognostic factors in primary ovarian carcinoma

This study aims to investigate the expression of P-glycoprotein (PGP), glutathione S-transferase pi (GST-pi), DNA topoisomerase II (Topo-II) and lung resistance-related protein (LRP) in ovarian carcinoma, thus providing better chemotherapy choice and post-operative prognosis for ovarian carcinoma patients. A total of 80 primary ovarian carcinoma, 16 benign ovarian epithelial neoplasm, and 12 normal ovarian tissue samples were collected. Immunohistochemistry was used to detect the expression of PGP, GST-pi, Topo-II and LRP, and the results were analysed by correlation with clinicopathological parameters. Positive expression rates of PGP, GST-pi, Topo-II and LRP in patients with ovarian carcinoma (57.5%, 58.8%, 76.3% and 73.8%, respectively) were all higher than those found in normal and benign tissue (P<0.05). In clinical stages I/II vs. III/IV, the expression rates of PGP, GST-pi, Topo-II and LRP were 40.7% vs. 66% (P<0.05), 40.7% vs. 67.9% (P<0.05), 66.7% vs. 81.1% (P>0.05) and 55.6% vs. 83.0% (P<0.05), respectively. Carcinoma differentiation ranged from well to poor, and expression levels of each marker were as follows: PGP, 57.9%, 62.1% and 53.1% (P>0.05); GST-pi, 36.8%, 55.2% and 75.0% (P<0.05); Topo-II, 52.6%, 79.3% and 87.5% (P<0.05); and LRP, 84.2%, 69.0% and 71.9% (P>0.05). Ovarian carcinoma patients with PGP-, GST-pi-, Topo-II- and LRP-positive expression had a shorter median survival time than those who were negative for these markers (PGP: 36 months vs. 48 months [P=0.0017]; GST-pi: 36 months vs. 41 months [P=0.0103]; Topo-II: 37 months vs. 39 months [P=0.3811]; LRP: 37 months vs. 55 months [P=0.002]). COX regression analysis demonstrated that the clinical stage of the tumour, and the expression of PGP, GST-pi or LRP, may influence patient survival time after surgery. The relative death risk for patients with clinical stage III/IV tumours increased 9.46-fold compared to those with stage I/II tumours. The relative death risk in the PGP-, GST-pi- and LRP-positive groups increased by 2.049-, 2.452- or 2.609-fold, respectively, compared with the corresponding negative groups. PGP, GST-pi, Topo-II and LRP are all expressed in primary ovarian carcinoma, indicating the presence of multidrug resistance in this disease. Combined evaluation of PGP, GST-pi, Topo-II and LRP expression may enable better chemotherapeutic choice and provide an accurate prognosis for ovarian carcinoma patients.