IMMUNOHISTOCHEMICAL EXPRESSION OF GLUTATHIONE-S-TRANSFERASE-PI CAN PREDICT CHEMOTHERAPY RESPONSE IN PATIENTS WITH NONSMALL CELL LUNG-CARCINOMA

BACKGROUND. Resistance to chemotherapy agents is a major problem in th e treatment of patients with nonsmall cell lung carcinoma (NSCLC), Rec ent studies have indicated that glutathione S-transferase-pi (GST-pi) may play an important role in the resistance of cancer cells to alkyla ting agents, including cisplatin compounds. METHODS, The expression of GST-pi in tissues obtained by bronchoscopic biopsy from 38 NSCLC pati ents was investigated immunohistochemically. These patients were treat ed with a combination of cisplatin-based chemotherapy and were evaluat ed to determine the relationship between GST-pi expression and chemoth erapy response. RESULTS, Of the 38 patients, 25 (66%) were GST-pi-posi tive and 13 (34%) were negative. There was no significant correlation between GST-pi expression and the clinicopathologic factors examined ( age, sex, performance status, histology, differentiation grade, and st age). Of the 38 patients treated with cisplatin-based chemotherapy, 12 patients responded to chemotherapy (overall response rate, 32%). For the patients with negative GST-pi expression, the response rate was 69 % (9 of 13 patients). In the patients with positive GST-pi expression, the response rate was 12% (3 of 25 patients). This difference was sta tistically significant (P=0.0012). CONCLUSIONS, The expression of GST- pi in NSCLC patients was significantly related to response to cisplati n-based chemotherapy, and may be a useful predictor of chemotherapy re sponse. (C) 1996 American Cancer Society.