In contrast to the BCR-ABL1-positive ALL-subgroup which clearly exhibited breakpoint-specific signals upon remission likely originating from a rearrangement persisting in the hematopoietic stem cell population, non-V(D)J rearrangements in general revealed MRD kinetics that were very similar to conventional IG/TR-V(D)J rearrangements (Fig. 4 and Table 3)41. The gene discussed is ABL1; the disease is acute lymphoblastic leukemia.