deletion as an MRD-dependent risk factor in childhood B-ALL: A post hoc analysis from a prospective cohort.

The effect of alterations on childhood B-cell acute lymphoblastic leukemia (B-ALL) remains unclear. To investigate the prognostic value of deletion ( ) and mutation ( ), this post hoc study used fluorescence in situ hybridization test to detect in 907 newly diagnosed B-ALL patients from a prospective cohort of Chinese Children's Cancer Group ALL-2015 trial. Targeted gene sequencing was used to identify in 342 out of the 907 patients. was detected in 4.4% of patients. The frequency of hypodiploidy was higher in subgroup (7.5% vs. 0.5%,  = 0.002), but patients with were less likely to have other recurrent genetic abnormalities, including rearrangements. Univariable and multivariable analyses indicated that was an independent risk factor for overall survival (OS) and disease-free survival (DFS). Furthermore, stratification analysis revealed that was associated with lower 5-year DFS in patients with positive minimal residual disease (MRD) after induction in the intermediate-risk group (0.0% vs. 58.0% [95% confidence interval [CI] 49.2%-68.3%],  < 0.001), suggesting an MRD-dependent pattern. However, somatic was not associated with poor survival (81.8% [95% CI 61.9%-100.0%] vs. 84.9% [95% CI 81.1%-89.0%],  = 0.971). In summary, may serve as a predictor for poor prognosis in pediatric B-ALL. In particular, children in the intermediate-risk group with positive MRD and may require more aggressive treatment.