IKZF1 and precursor B-cell acute lymphoblastic leukemia: Overall, about 40%–49% of B-ALL carried gene CNVs that regulate early B-line cell differentiation and development-related genes (e.g., PAX5, IKZF1, and EBF1) and about 60% carry deletions of cell-cycle regulatory genes (e.g., CDKN2A/B and RB1) (5, 14).