IKZF1 and acute lymphoblastic leukemia: The study conducted by the international multicenter trial AIEOP-BFM ALL 2000 on 991 patients showed that only ~53% of patients with the IKZF1 plus type had a 5-year event-free survival, compared to ~79% of patients with IKZF1 deletion alone and ~87% in patients without the IKZF1 deletion.