CRLF2 and acute lymphoblastic leukemia: In addition, various genomic analyses detected chromosomal rearrangements and alterations of genes encoding TSLPR/CRLF2 in a large number of patients with B-cell precursor ALL (BCP-ALL), all of them having in common either an enhanced or constitutive expression of TSLPR leading to a signal boost resulting in resistance to therapy, high recurrence rate, and poor clinical outcome (17–19).