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 chemotherapeutic agents occur during the treatments. Recent studies have indicated that glutathione S-transferase-pi (GST-pi) may play an important role in the resistance of cancer cells to alkylating agents, including cisplatin compounds. We examined a possible relationship between immunohistochemical expression 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). In the patients with positive GST-pi expression, the response 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 and may be useful as a predictor of chemotherapy response.