Two subgroups of CRLF2-overexpressing pediatric acute lymphoblastic leukemias differ in outcome and gene expression

Overexpression of the cytokine receptor-like factor 2 (CRLF2) gene in acute lymphoblastic leukemia (ALL) is caused by different aberrations like a deletion juxtaposing CRLF2 with the P2RY8 promoter, by a translocation involving the immunoglobulin heavy chain locus ([email protected]), by supernumerary copies of the CRLF2 locus or by not yet identified causes. However, only the presence of the P2RY8-CRLF2 rearrangement is associated with a high incidence of relapse in CRLF2-overexpressing precursor B-cell ALL (pB-ALL) in children.