In Ph-like ALL, rearrangements with the immunoglobulin heavy chain locus (IGH-CRLF2) and a focal interstitial deletion, joining CRLF2 to the adjacent P2RY8 gene (P2RY8-CRLF2), result in CRLF2 overexpression and increase CRLF2 protein expression [24,30]. Here, CRLF2 is linked to acute lymphoblastic leukemia.