Prognostic value of GST-p expression in diffuse large B-cell lymphomas.

Among mechanisms potentially involved in resistance to alkylating agents and anthracyclines, the glutathione system has been extensively studied in vitro. We analyzed by immunohistochemistry the relation between glutathione s-transferase &pie; (GST-&pie;) expression in tumor cells and outcome in 69 cases of diffuse large B-cell NHL (DLBCL). GST-&pie; expression was considered as low when <50% of tumor cells were stained and high when &ges;50% tumor cells were stained. Median follow-up was 58 months. GST-&pie; expression was correlated with the probability of achieving complete remission (CR). Patients with high GST-&pie; expression had a worse 5-year freedom from progression (FFP). High GST-&pie; expression was associated with a trend for lower survival. In the group of patients with International Prognostic Index (IPI) 0-1, low GST-&pie expression was associated with a CR rate of 88%, a 5-year FFP of 76±20% and a 5-year survival of 78±16% compared to 36, 14±16 and 40±32%, respectively, in patients with a high GST-&pie; expression (P=0.002, P<10[SUP-5] and P=0.01, respectively). No correlation was found between GST-&pie; expression and lactico deshydrogenase serum level, age, Ann Arbor stage, performance status, and IPI index. Both GST-&pie; expression and the IPI index correlated with FFP. After incorporating IPI and GST-&pie; expression in a multivariate analysis for FFP, GST-&pie; expression remained the only prognostic factor (P=0.003). Our findings suggest that GST-&pie; expression had strong prognostic significance in DLBCL, which appears to be independent of other prognostic parameters in those disorders. [ABSTRACT FROM AUTHOR]