CML in blast crisis: more common than we think?

摘要

In this issue of Blood, Hovorkova and colleagues assessed minimal residual disease (MRD) sequentially in children with Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL) via BCR-ABL1 genomic polymerase chain reaction (PCR) and immunoglobulin gene (IG)/T-cell receptor gene (TCR) PCR in parallel. Results were concordant in most patients, but >20% of children with Ph+ ALL had MRD levels that were >1 log higher with BCR-ABL1 genomic PCR than with IG/TCR PCR. Using cell sorting and fluorescence in situ hybridization (FISH) to study patients with discordant MRD results, the authors demonstrated conclusively that BCR-ABL1-positive cells were present in nonmalignant B cells, T cells, and myeloid cells, establishing that the translocation occurred in a multipotent hematopoietic progenitor cell and suggesting that these patients have a disease more akin to chronic myeloid leukemia (CML) in lymphoid blast crisis than Ph+ ALL.(1)