BACKGROUND: Molecular analysis of minimal residual disease is only applicable in acute myeloblastic leukemia (AML) patients with genetic markers (20-30%). This study analyzes the feasibility of the real-time quantitative polymerase chain reaction (RQ-PCR) assay to detect mutant nucleophosmin (NPM1) during follow-up in AML patients. Moreover, we compare the NPM1 results with those of WT1 expression to MRD assessment. METHODS: The study includes 97 samples from 24 AML patients with type A NPM1 mutation at diagnosis. MRD was evaluated simultaneous by RQ-PCR assay to detect NPM1-mutated and WT1 expression. RESULTS: The expression levels of WT1 and NPM1 in 93 paired samples showed a strong positive correlation (r=0.81; p<0.0001). However, the kinetics of disappearance were different, WT1 decreased rapidly after induction but maintained these residual levels after treatment in patients in complete remission, whereas NPM1 experienced a mild reduction after induction but was undetectable in long survivor patients. CONCLUSIONS: This study shows the feasibility of the RQ-PCR assay to monitor MRD in AML patients carrying NPM1 mutations and its advantage over RQ-PCR assay for WT1. Owing to NPM1-mutated is specific of leukemic cells and shows higher levels at presentation.
BACKGROUND: Molecular analysis of minimal residual disease is only applicable in acute myeloblastic leukemia (AML) patients with genetic markers (20-30%). This study analyzes the feasibility of the real-time quantitative polymerase chain reaction (RQ-PCR) assay to detect mutant nucleophosmin (NPM1) during follow-up in AMLpatients. Moreover, we compare the NPM1 results with those of WT1 expression to MRD assessment. METHODS: The study includes 97 samples from 24 AMLpatients with type A NPM1 mutation at diagnosis. MRD was evaluated simultaneous by RQ-PCR assay to detect NPM1-mutated and WT1 expression. RESULTS: The expression levels of WT1 and NPM1 in 93 paired samples showed a strong positive correlation (r=0.81; p<0.0001). However, the kinetics of disappearance were different, WT1 decreased rapidly after induction but maintained these residual levels after treatment in patients in complete remission, whereas NPM1 experienced a mild reduction after induction but was undetectable in long survivor patients. CONCLUSIONS: This study shows the feasibility of the RQ-PCR assay to monitor MRD in AMLpatients carrying NPM1 mutations and its advantage over RQ-PCR assay for WT1. Owing to NPM1-mutated is specific of leukemic cells and shows higher levels at presentation.
Authors: Nicolaus Kröger; Ulrike Bacher; Peter Bader; Sebastian Böttcher; Michael J Borowitz; Peter Dreger; Issa Khouri; Homer A Macapinlac; Homer Macapintac; Eduardo Olavarria; Jerald Radich; Wendy Stock; Julie M Vose; Daniel Weisdorf; Andre Willasch; Sergio Giralt; Michael R Bishop; Alan S Wayne Journal: Biol Blood Marrow Transplant Date: 2010-06-14 Impact factor: 5.742