Immunohistochemical expression of glutathione S-transferase-π can predict chemotherapy response in patients with nonsmall cell lung carcinoma

BACKGROUND. Resistance to chemotherapy agents is a major problem in the treatment of patients with nonsmall cell lung carcinoma (NSCLC). Recent studies have indicated that glutathione S-transferase-π (GST-π) may play an important role in the resistance of cancer cells to alkylating agents, including cisplatin compounds. METHODS. The expression of GST-π in tissues obtained by bronchoscopic biopsy from 38 NSCLC patients was investigated immunohistochemically. These patients were treated with a combination of cisplatin-based chemotherapy and were evaluated to determine the relationship between GST-π expression and chemotherapy response. RESULTS. Of the 38 patients, 25 (66%) were GST-π-positive and 13 (34%) were negative. There was no significant correlation between GST-π expression and the clinicopathologic factors examined (age, sex, performance status, histology, differentiation grade, and stage). Of the 38 patients treated with cisplatin- based chemotherapy, 12 patients responded to chemotherapy (overall response rate, 32%). For the patients with negative GST-π expression, the response rate was 89% (9 of 13 patients). In the patients with positive GST-π expression, the response rate was 12% (3 of 25 patients). This difference was statistically significant (P = 0.0012). CONCLUSIONS. The expression of GST- π in NSCLC patients was significantly related to response to cisplatin- based chemotherapy, and may be a useful predictor of chemotherapy response.