For acute myeloid leukemia (AML) with nucleophosmin 1 mutation (NPM1m), multiparameter flow cytometry (FCM) and real-time quantitative polymerase chain reaction (RQ-PCR) are used to monitor minimal residual disease (MRD).
For the NPM1-wt standard-risk subgroup, C2 MRD+ was significantly associated with poorer outcomes (OS, 33% v 63% MRD-, P = .003; relapse incidence, 89% when MRD+ ≥ 0.1%); transplant benefit was more apparent in patients with MRD+ (HR, 0.72; 95% CI, 0.31 to 1.69) than those with MRD- (HR, 1.68 [95% CI, 0.75 to 3.85]; P = .16 for interaction).
NPM1 mutation based MRD monitoring was more sensitive and predicted relapse earlier but IDH1/2 based monitoring was more sensitive than a method based on MLL-PTD.
When tested on follow-up samples from a patient with acute myeloid leukemia, targeted deep sequencing of single nucleotide variations as well as NPM1 was more sensitive than minimal residual disease quantification with multiparameter flow cytometry.
To simplify and improve MRD testing for NPM1, we present a novel digital PCR technique composed of massively multiplex pools of insertion-specific primers that selectively detect mutated but not wild-type NPM1.
This commentary highlights the article by Mencia-Trinchant et al that describes a novel digital PCR assay for sensitive detection of minimal residual disease in NPM1 mutated acute myeloid leukemia.
Purpose This study assessed the prognostic impact of postinduction NPM1-mutated ( NPM1m) minimal residual disease (MRD) in young adult patients (age, 18 to 60 years) with acute myeloid leukemia, and addressed the question of whether NPM1m MRD may be used as a predictive factor of allogeneic stem cell transplantation (ASCT) benefit.
Areas covered: Available techniques include multi-color flow cytometry (MFC) of leukemia associated immunophenotypes (LAIP), quantitative reverse transcriptase polymerase chain reaction (QRT-PCR) for detecting fusion and mutated genes (RUNX1-RUNX1T1, CBFB-MYH11, and NPM1), overexpression of genes such as WT1, and next generation sequencing (NGS) for MRD.
Since most current NPM1 RQ-PCR MRD protocols suffer from clear definitions of quantifiability, we sought to define quantifiability in a reproducible and standardized manner.
We used a reverse-transcriptase quantitative polymerase-chain-reaction assay to detect minimal residual disease in 2569 samples obtained from 346 patients with NPM1-mutated AML who had undergone intensive treatment in the National Cancer Research Institute AML17 trial.
Our data showed that the pre-transplant level of MRD in patients with normal karyotype AML harboring NPM1 mutation in CR provides important prognostic information, which as an independent prognostic factor predicts transplant results.
Flow MRD was prognostic within the intermediate cytogenetic risk group (5-year RFS 15% vs 37%, P=0.016) as well as for patients with normal karyotype and NPM1 mutations (5-year RFS 13% vs 49%, P=0.02) or FLT3-ITD (3-year RFS rates 9% vs 44%, P=0.016).
Our study supports the prognostic significance of MRD assessed by WT1 and NPM1mut transcript levels and show that NPM1MRD is decreased by GO treatment.
In this study we investigated the prognostic potential of minimal residual disease monitoring by quantitative real-time polymerase chain reaction analysis of NPM1 mutations in patients treated in the AMLCG 1999, 2004 and 2008 trials.
In addition, blasts of patients with mutant nucleophosmin (NPM1) revealed significantly higher CD33 and CD123 expression pointing toward the possibility of minimal residual disease-guided interventions in mutated NPM1-positive AMLs.
Mutations of the NPM1 gene (NPM1mut) are among the most common genetic alterations in acute myeloid leukemia and are suitable for minimal residual disease detection.
Imaging flow cytometry has the potential to be included as part of a standard flow cytometry antibody panel to identify potential NPM1 mutations as part of diagnosis and minimal residual disease monitoring.
We compared the clinical value of minimal residual disease (MRD) monitoring by cytofluorimetric methods, Wilms tumor gene 1 (WT1) expression and the study of nucleophosmin gene (NPM) mutations in a series of 26 patients with NPM-mutated de novo acute myeloid leukemia (NPM-AML) who achieved complete hematological remission after conventional chemotherapy.