Hybridization of CRLF2 break / IGH fusion probe to a metaphase spread showing normal pattern (2RG2B).
CRLF2-IGH fusions between Xp22-14q32 or Yp11-14q32 results in a deregulated expression of the cytokine receptor gene (CRLF2). This can also be the result of the fusion with the P2RY8 promoter on Xp22 or Yp11. Gain of chromosome X has been observed in Down syndrome-associated ALL. The CRLF2 (Xp22/Yp11) Break/IGH (14q32) Fusion Triple-Color FISH probe is optimized to detect translocations involving the CRLF2 gene at region Xp22 and Yp11. The probe shows a break between red and green in case of a translocation with CRLF2 and IGH involvement. In case of a fusion with the P2RY8 gene on Xp22 or Yp11, one red probe is deleted. For fusion confirmation to the IGH gene, a blue probe covering IGH is added.
References: Mullighan et al., 2009, Nat. Genet. 41(11): 1243-1246. Russell et al., 2009, Blood, 114(13): 2688-2698.