Next-generation sequencing for minimal residual disease monitoring in acute myeloid leukemia patients with FLT3-ITD or NPM1 mutations.

Systematic assessment of minimal residual disease (MRD) in acute myeloid leukemia (AML) patients has been hampered by lack of a reliable, uniform MRD marker applicable to all patients. We evaluated next-generation sequencing (NGS) for MRD assessment in AML patients (n = 80 samples). The ability of NGS technologies to generate thousands of clonal sequences makes it possible to determine the allelic ratio of sequence variants. Using NGS, we were able to determine the allelic ratio of different FLT3-internal tandem duplication (ITD) clones within one patient sample, in addition to resolution of FLT3-ITD insertion site, length, and sequence in a single analysis. Furthermore, NGS allowed us to study emergence of clonal dominance. Parallel assessment of MRD by NGS and quantitative real-time polymerase chain reaction in NPM1 mutated patients was concordant in 95% of analyzed samples (n = 38). The frequency of mutated alleles was linearly quantified by NGS. As NGS sensitivity is scalable depending on sequence coverage, it reflects a highly flexible and reliable tool to assess MRD in leukemia patients.