In 2013, Meyer et al. characterized ΔIKZF1 in pediatric BCP-ALL patients, and described for the first time an IKZF1-COBL tail-to-tail fusion as a consequence of an ~800 kb interstitial deletion between IKZF1 intron 1 and COBL intron 5 [12]. Here, IKZF1 is linked to acute lymphoblastic leukemia.