CRLF2 and acute lymphoblastic leukemia: Similarly,CRLF2 rearrangement (CRLF2r) that is sometimes used to define the subset of patients within B-other ALL45 is frequently a secondary aberration46 and also occurs across several BCP-ALL subtypes (BCR-ABL1-positive ALL,BCR-ABL1-like ALL, and hyperdiploid and hypodiploid ALL)11,41,47,48.