Other studies reveal that overexpression of cytokine receptor–like factor 2 (CRLF2) due to IgH@-CRLF2 fusion resulting from immunoglobulin heavy-chain locus (IgH@) translocation or P2RY8-CRLF2 fusion resulting from the interstitial deletion of the pseudoautosomal region 1 (PAR1) of either of the sex chromosomes (Xp22/Yp11) was significantly associated with JAK2 mutations, IKZF1 alterations, and a poor outcome in BCP-ALL [19–25]. This evidence concerns the gene JAK2 and acute lymphoblastic leukemia.