In B-cell acute lymphoblastic leukemia (B-ALL), a new subtype has emerged calledBCR-ABL1-like subtype (15% of pediatric ALL and 50% of ALL with Down syndrome), as it exhibits a transcriptional profile similar to that ofBCR-ABL1–positive ALL with poor prognosis42. The gene discussed is ABL1; the disease is B-cell acute lymphoblastic leukemia.