FLT3 mutations do not influence MDR-1 gene expression in acute myeloid leukemia

Background: A worse outcome for patients carrying FLT3 mutations or expressing MDR1 gene has been reported. This study was designed to verify the possible co-expression of mutated-FLT3 and MDR1 genes and to evaluate their independent prognostic role. Patients and Methods: Sixty-one AML patients were tested for MDR1-mRNA levels by real-time PCR and for FLT3 mutations by PCR and Genescan analysis. Results: FLT3 mutations were detected in 31% of patients, more frequently in patients <60 years and at standard cytogenetic risk Among 92% of patients MDR1-positive, 50% expressed high levels of mRNA. No significant correlation was found between FLT3 mutations and high levels of MDR1. FLT3 or MDR1 mutations failed to show any role concerning the CR achievement and OS. On the contrary, a significant disadvantage for DFS was found in the group of patients carrying FLT3/ITD. Conclusion: The results reported above show that FLT3 mutations and MDR1 expression represent two independent clinical prognostic factors for AML patients.