ASSOCIATION BETWEEN EXPRESSION OF GLUTATHIONE-ASSOCIATED ENZYMES AND RESPONSE TO PLATINUM-BASED CHEMOTHERAPY IN HEAD AND NECK-CANCER

We examined the correlation between response to platinum-based chemoth erapy and expression of glutathione S-transferase (GST), gamma-GGT (bo th by immunohistochemistry) and gamma-GCS (by in situ hybridization) i n 51 patients with head and neck cancer, who received a total of 56 co urses of chemotherapy. The overall response rate for the 56 chemothera py treatment courses was 48%. The overall response rate (CR, PR) for p atients with low GST scores was 88% (21 of 24), while among the patien ts with high GST scores, the overall response rate was 19% (6 of 32, P = 0.001). Patients with a low GST score were 4.7 times more likely to respond to chemotherapy than patients with high GST scores. GST score s corresponded to response in 84% of cases. Among 33 patients treated with chemotherapy for relapsed disease, the overall response rate for patients with low GST score was 70% (7 of 10), while among the patient s with high GST scores, the overall response rate was 8.7% (2 of 23, P < 0.001). In contrast, both gamma-GCS and gamma-GGT showed a range of expression in these samples, but there was no significant correlation with treatment response. We conclude that GST expression correlates w ell with response to platinum based chemotherapy in head and neck canc er. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.