Childhood Acute B-Lineage Lymphoblastic Leukemia With CDKN2A/B Deletion Is a Distinct Entity With Adverse Genetic Features and Poor Clinical Outcomes.

To further emphasize the clinical-genetic features and prognosis of deletions in childhood acute lymphoblastic leukemia (ALL), we retrospectively analyzed 819 consecutive B-ALL patients treated with the Chinese Children's Cancer Group ALL-2015 (CCCG-ALL-2015) protocol, and fluorescence hybridization (FISH) analysis on deletion was available for 599 patients. The prevalence of gene deletions was 20.2% (121/599) of B-ALL. deletions were significantly associated with older age, higher leukocyte counts, a higher percentage of hepatosplenomegaly, and a higher frequency of ( < 0.05). Those patients achieved similar minimal residual disease (MRD) clearance and complete remission compared to patients without deletion. The deletions were correlated with inferior outcomes, including a 3-year event-free survival (EFS) rate (69.8 ± 4.6 vs. 89.2 ± 1.6%, = 0.000) and a 3-year overall survival (OS) rate (89.4% ± 2.9% vs. 94.7% ± 1.1%, = 0.037). In multivariable analysis, deletion was still an independent prognostic factor for EFS in total cohorts ( < 0.05). We also detected a multiplicative interaction between deletions and TP53 deletion on dismal prognosis (-interaction < 0.05). In conclusion, deletion is associated with distinct characteristics and serves as a poor prognostic factor in pediatric ALL, especially in TP53 deletion carriers.