Considering that IKAROS is indispensable for B-cell commitment, several studies have shown that B-ALL patients with IKZF1 abnormalities have a poor prognosis, a 3-fold increase in the risk of relapse after treatment [11,72] and a reduced 5-year event-free survival (EFS) of 61% compared to 87% for those without this abnormality [73]; in contrast, only 5% of patients with T-cell ALL harbor the loss of an IKAROS allele [2,74]. Here, IKZF1 is linked to acute lymphoblastic leukemia.