Duplication 1q is highly correlated with poor prognosis in high hyperdiploid pediatric B-acute lymphoblastic leukemia.

Background: The role of structural abnormalities in high hyperdiploidy (HeH) has been debatable, with few studies that addressed recurrent translocations with concurrent HeH (t-HeH). We aimed at the characterization of HeH cases in pediatric B-acute lymphoblastic leukemia (B-ALL) patients with special emphasis on the structural abnormalities including t-HeH.

Patients And Methods: Our study included all patients diagnosed with HeH over the period from January 2016 to April 2019 presenting to the Pediatric Oncology Department, National Cancer Institute, Cairo University.

Results: Among 480 de novo B-ALL pediatric patients, HeH was detected in eighty (16.7%) cases with a median age of 5 years. t-HeH was identified in 17/480 (3.5%) cases: 9(1.9%) with t(12;21), 7(1.5%) with t(9;22), and 1(0.2%) with t(4;11). Duplication (1q) was the most prevalent structural abnormality in c-HeH (hyperdiploidy without recurrent translocations) (n = 12,15%). Children ≥10 years or presenting with white blood cells (WBC) ≥50 × 10 /L) had an inferior 3 year-overall survival as compared to younger children (P = .003), and to lower WBC (P = .02). Duplication (1q) was an independent adverse parameter on the disease-free survival (DFS) of c-HeH patients (P = .004).

Conclusions: Older age and WBC ≥ 50 × 10 /L were adverse prognostic factors. Duplication (1q) is correlated with lower DFS in c-HeH patients. t-HeH has distinct patterns of chromosomal gain.