Clonal Dynamics and Relapse Risk Revealed by High-Sensitivity FLT3-Internal Tandem Duplication Detection in Acute...

Area of Science:

• Hematology
• Molecular Biology
• Oncology

Background:

• Detecting minimal residual disease in acute myeloid leukemia (AML) is crucial for understanding clonal heterogeneity and relapse.
• FLT3-ITD mutations are common, targetable, and prognostically significant in AML, but require sensitive detection methods.

Purpose of the Study:

• To develop and validate a high-sensitivity next-generation sequencing (HS-NGS) assay for detecting low-level FLT3-ITD mutations in AML.
• To investigate the clinical significance of FLT3-ITD subclones at diagnosis and their impact on relapse risk.
• To characterize FLT3-ITD clonal evolution patterns during AML treatment and relapse.

Main Methods:

• Development of a novel HS-NGS assay capable of detecting FLT3-ITD mutations at a variant allele frequency of 1x10^-5.
• Application of the HS-NGS assay to 289 longitudinal samples from 62 AML patients.
• Pairwise sequencing of diagnosis and relapse samples from 23 patients to analyze clonal evolution.

Main Results:

• The HS-NGS assay reliably detected low-level FLT3-ITD mutations.
• Frequent occurrence of FLT3-ITD subclones was observed at diagnosis.
• Clearance of FLT3-ITD mutations post-induction was associated with a significantly decreased relapse risk.
• Rising FLT3-ITD levels during follow-up predicted impending relapse.
• Detailed patterns of FLT3-ITD clonal evolution at relapse were elucidated.

Conclusions:

• High-sensitivity FLT3-ITD testing has emerging clinical utility in AML management.
• Understanding clonal dynamics through sensitive mutation detection improves prognostic accuracy.
• HS-NGS assays enhance the detection of minimal residual disease and inform therapeutic strategies in FLT3-ITD positive AML.