Immunohistochemical Expression of Glutathione S-Transferase π (GST-π) and Chemotherapy Response in Malignant Ovarian Tumors

Objectives: To clarify the relationship between the expression of GST-π and the therapeutic effects of high-dose combination chemotherapy with support by autologous bone-marrow transplantation (ABMT). Methods: Expression of GST-π in tissue specimen were analyzed by indirect immunoperoxidase methods using anti-GST-π polyclonal antibody. Results: (1) Eighteen of 36 cases (50%) tested prior to administration of any chemotherapeutic agents were found to be positive in terms of immunohistochemical expression of GST-π in the cancer cells. (2) The rate of GST-π expression was elevated following administration of cisplatin, adriamycin, and cyclophosphamide, which suggests that administration of such anti-cancer agents is capable of inducing expression of GST-π in cancer cells. (3) GST-π negative patients exhibit better survival rates than do GST-π positive patients (Kaplan Meier method: p < 0.05-0.001). Conclusions: Analysis of GST-π obtained at primary surgery can serve as a valid marker in anticipating chemotherapeutic effects and long-term prognoses.