Changes in the MDR1 gene expression after short-term ex vivo therapy with prednisolone have prognostic impact in childhood acute lymphoblastic leukemia.

Multidrug resistance 1 (MDR1) gene expression determined by real-time polymerase chain reaction and results of rhodamine assay were analyzed at diagnosis and after 3 days of ex vivo therapy with prednisolone in 36 pediatric patients with acute lymphoblastic leukemia (ALL). Only 62% patients with de novo ALL had significant decrease of MDR1 expression. These patients had over twofold lower rhodamine retention in the presence of cyclosporine A on day 3 than others and had better probability of disease-free survival. In this study, we have shown that changes in the expression of MDR1 gene after short-term incubation of lymphoblasts with prednisolone may have prognostic value in pediatric de novo ALL patients.