Glutathione S-transferase and P-glycoprotein expressions in neuroblastoma

This study was planned to evaluate the prognostic role of glutathione S-transferase pi (GST-pi) and P-glycoprotein (P-gp) expressions in children with neuroblastoma. Sections from formalin-fixed paraffin-embedded tumor blocks from 52 neuroblastoma cases (17 with localized, 35 with advanced disease) were subjected to immunohistochemistry for P-gp and GST-pi expressions. The overall number of tumors positive for P-gp and GST-pi were 19 (36.5%) and 21 (40.4%), respectively. Twenty-two tumors were negative for both GST-pi and P-gp expressions, whereas 10 expressed both proteins. The distribution of staining status of samples in the groups of both proteins showed no significant difference. No relation between the expressions of both proteins and the clinical characteristics of the patients was demonstrable. The differenes between the survival rates of patients with positive and negative staining for P-gp expression were not statistically significant. Although 2 common mechanisms of multiple drug resistance, P-gp and GST-pi, might be responsible for drug resistance in neuroblastoma, this complex mechanism has no direct significant impact on prognosis. Multiple mechanisms at cellular levels are responsible for the resistance against antineoplastic therapies in neuroblastoma.