Amongst subjects achieving complete remission those with IKZF1 deletion had similar 5-year non-relapse mortality (NRM) (11 % [2–20 %] vs. 16 % [4–28 %]; P = 0.736), a higher 5-year cumulative incidence of relapse (CIR) (55 % [35–76 %] vs. 25 % [12–38 %]; P = 0.004), and worse 5-year leukemia-free survival (LFS) (33 % [16–52 %] vs. 59 % [42–73 %]; P = 0.012) and survival (48 % [33–62 %] vs. 75 % [57–86 %]; P = 0.002). Here, IKZF1 is linked to leukemia.