Next-generation antigen receptor sequencing of paired diagnosis and relapse samples of B-cell acute lymphoblastic leukemia: Clonal evolution and implications for minimal residual disease target selection

•NGS shows that IG/TR gene rearrangements in ALL patients are frequently oligoclonal.•Clonal evolution between diagnosis and relapse is common.•Major clones should be identified by frequency but particularly by absolute size.•Major clonal IG/TR rearrangements are much more stable than subclones.•Our algorithm allows selection of stable MRD-PCR targets in >97% of ALL patients.