title: Monitoring minimal residual disease in acute myeloid leukaemia with NPM1 mutations by quantitative PCR: clonal evolution is a limiting factor.
abstract: Nucleophosmin (NPM1) mutations in exon 12 represent the most frequent molecular aberrations in adult patients with acute myeloid leukaemia (AML). Molecular detection of NPM1 mutation A could be a useful marker for routine monitoring of minimal residual disease (MRD). We established a calibrator-normalized relative quantification real-time polymerase chain reaction (PCR) assay for NPM1 mutation A. ABL1 was used as a reference housekeeping gene and the NPM1 mutation A-containing OCI/AML3 cell line as a calibrator. Relative quantification was performed by calculating the NPM1 mutation A/ABL1 ratio which was normalized to the NPM1 mutation A/ABL1 ratio of OCI/AML3 calibrator cDNA. The assay showed a sensitivity of 10(-5). The clinical usefulness was evaluated by monitoring MRD in 51 AML patients with NPM1 mutation A. In 27 patients analysed at diagnosis and after induction treatment, NPM1 mutation A ratios showed a median log(10) reduction of 2.48, which correlated with response to therapy. Among the 51 patients, 21 relapsed and two lost the mutation. We established a sensitive, specific and reproducible assay for routine quantification and monitoring of NPM1 mutation A levels. However, clonal evolution was observed in 9.5% limiting the usefulness of the NPM1 mutation A mutation as a molecular marker in these patients.
authors.affiliation: Laboratory for Leukaemia Diagnostics and Department of Medicine III, University Hospital Grosshadern, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Papadaki
authors.forename: Annika
authors.initials: A
authors.lastname: Dufour
authors.forename: Marlene
authors.initials: M
authors.lastname: Seibl
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schneider
authors.forename: Stefan K
authors.initials: SK
authors.lastname: Bohlander
authors.forename: Evelyn
authors.initials: E
authors.lastname: Zellmeier
authors.forename: Gudrun
authors.initials: G
authors.lastname: Mellert
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hiddemann
authors.forename: Karsten
authors.initials: K
authors.lastname: Spiekermann
mesh_terms: D000328:Adult; D000368:Aged; D005819:Genetic Markers; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D008875:Middle Aged; D009154:Mutation; D018365:Neoplasm, Residual; D014411:Neoplastic Stem Cells / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics*; D000090243:Nucleophosmin; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D005819:Genetic Markers; C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D000090243:Nucleophosmin