MESSENGER-RNA EXPRESSION OF RESISTANCE FACTORS AND THEIR CORRELATION TO THE PROLIFERATIVE ACTIVITY IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

In this report we analyzed the mRNA expression of the resistance-relat ed enzymes DNA topoisomerase II (Topo II), thymidylate synthase (TS), glutathione S-transferase-pi (GST-pi) and glutathione peroxidase (GP) in childhood acute lymphoblastic leukemia (ALL) and their correlation to the proliferative activity, determined by Ki-67. RNA of blast cells from 54 children with untreated ALL were examined by dot blot hybridi zation. We found a significant positive correlation between Topo II an d TS and cell proliferation. No significant correlation was detected b etween the mRNA expression of the glutathione-dependent enzymes GST-pi or GP and Ki-67. The results were substantiated by a semiquantitative RT-PCR-assay and by immunocytochemistry.