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

The ability to detect low-level disease is key to our understanding of clonal heterogeneity in acute myeloid leukemia (AML) and residual disease that elude conventional assays and seed relapse. We developed a high-sensitivity next-generation sequencing (HS-NGS) clinical assay, able to reliably detect low levels (1 × 10) of FLT3-ITD, a frequent, therapeutically targetable and prognostically relevant mutation in AML. By applying this assay to 289 longitudinal samples from 62 patients at initial diagnosis and/or clinical follow-up (mean follow-up of 22 months), we reveal the frequent occurrence of FLT3-ITD subclones at diagnosis and demonstrate a significantly decreased relapse risk when FLT3-ITD is cleared after induction or thereafter.

Side scatter ratio of the CD105-positive and CD105-negative red blood cell fractions is useful for the detection of low-grade myelodysplastic neoplasms by flow cytometry.

Objectives: We assessed the utility of red blood cell (RBC) CD105 and side scatter (SSC) parameters by flow cytometry for the detection of low-grade myelodysplastic neoplasms (MDS) in bone marrow specimens.

Methods: Ten RBC parameters incorporating CD105 or SSC combined with the Meyerson-Alayed scoring system (MASS) metrics were retrospectively evaluated by flow cytometry for utility in detecting low-grade MDS (n = 56) compared with cytopenic controls (n = 86).

Results: Myelodysplastic neoplasms were associated with 7 of the RBC parameters in univariate analysis.