Next-Generation Sequencing for Minimal Residual Disease Surveillance in Acute Lymphoblastic Leukemia: An Update.

Monitoring minimal residual disease (MRD) is an important predictor of outcome in acute lymphoblastic leukemia (ALL) and is used in risk stratification, prognosis determination, and therapy guidance. Several laboratory techniques have proven utility for characterizing leukemic cells and following MRD through diagnosis, remission and possible recurrence. Methods for determining MRD are based on the detection of leukemia-specific aberrant immunophenotypes by mulitparameter flow cytometry or the evaluation of leukemia-specific rearranged immunoglobulin or T-cell receptor sequences by quantitative real-time PCR. Next-generation sequencing (NGS) is emerging as a new flexible and sensitive tool to detect MRD, which allows identification of clonal composition and scalable sensitivity depending on sequence coverage. As NGS becomes more accessible and affordable, guidelines should be established for its application to MRD surveillance.