Quantitative analysis of IKZF1 gene deletions in pediatric B-cell precursor acute lymphoblastic leukemia: Higher levels are associated with a poorer prognosis

Abstract Purpose: To assess the prognostic effect of different levels of IKZF1 gene deletions in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL).Methods: IKZF1 Δ2-8/ALB deletions were quantified using multiplex real-time quantitative PCR in newly diagnosed pediatric BCP-ALL patients. Seventy-four patients with IKZF1 deletions ≥ 0.01% were included. Clinical characteristics, laboratory data, and treatment outcomes were analysed.Results: The patients were divided into two groups: IKZF1 deletions < 1% (group A) and ≥ 1% (group B). Group B patients had a higher BCR-ABL1 positive rate than did group A patients. The proportions of patients who had an age at onset ≥10 years old, and white blood cell count ≥ 50×109/L were significantly higher in group B than in group A. The 3-year overall survival (OS) and 3-year event-free survival (EFS) rates in group B were 79 ± 8.8% and 62.4 ± 9.7%, respectively, being significantly lower than those in group A (97.7 ± 2.2% and 83.2 ± 5.8%, respectively). The level of IKZF1 deletions ≥ 1% and the central nervous system leukemia were independent risk factors of EFS.Conclusions: Pediatric BCP-ALL patients with high levels of IKZF1 gene deletions have a poorer prognosis than those with low levels.