Immunohistochemical expression of glutathione transferase-pi in untreated primary non-small-cell lung cancer

Patients with unresectable non-small-cell. lung cancer (NSCLC) usually have undergone chemotherapy; however, such problems as resistance to chemothera peutic agents occur during the treatments. Recent studies have indicated th at glutathione S-transferase-pi (GST-pi) may play an important role in the resistance of cancer cells to alkylating agents, including cisplatin compou nds. We examined a possible relationship between immunohistochemical expres sion of GST-pi and the response to cisplatin plus etoposide chemotherapy in patients with untreated and unresectable primary NSCLC, Of the 89 patients , 50 (56.2%) were GST-pi-positive and 39 (43.8%) were GST-pi-negative. For the patients with negative GST-pi expression, the response rate was 66.7% ( 26 of 39 patients). Tn the patients with positive GST-pi expression, the re sponse rate was 26% (13 of 50 patients). This difference was statistically significant (P = 0019). The results suggest that GST-pi expression in NSCLC tissues is related to response to cisplatin plus etoposide chemotherapy an d may be useful as a predictor of chemotherapy response.