The Double-Faced t(12;21) in Pediatric B-cell Precursor Acute Lymphoblastic Leukemia Patients: Seven Years Experience at a Tertiary Center.

BACKGROUND

ETV6:RUNX1 has a good prognosis in pediatric acute lymphoblastic leukemia (ALL). However, it shows a controversial prognostic pattern due to the increased risk of late relapses. We aimed to analyze the clinico-laboratory features and treatment outcomes of patients with ETV6::RUNX1.

METHODS

This study involved newly diagnosed precursor B-ALL pediatric patients who had the ETV6::RUNX1 fusion gene between January-2016 and December-2022, in the National Cancer Institute (NCI), Cairo University.

RESULTS

Out of 645, 111 (17.2%) tested positive for ETV6::RUNX1. The mean age was 5.2 years (SD ± 2.9). Conventional cytogenetic analysis revealed that 54.2% (39/71) had concurrent chromosomal aberrations. Younger age (< 10 years) and initial leukocyte count ≤ 50,000/µl were associated with better remission outcomes (P < .001 and P = .03, respectively). Overall survival (OS) was significantly affected by the remission status on day 15 (P = .001) and disease risk (P = .006). Additionally, disease-free survival (DFS) was negatively impacted by splenomegaly (P = .042), the immunophenotyping of c-ALL (P = .01), and the presence of aberrant myeloid markers (P = .001). Twelve patients (10.8%) experienced relapses. The 5-year estimated cumulative incidence of relapse (CIR) was significantly lower for hypodiploidy and high hyperdiploidy when compared to the modal chromosomal number (MCN) of 47 to 50 chromosomes (0%, 0% vs. 21%, P < .001). Multivariate analysis identified the initial platelet count < 40 × 10³/mL as an adverse independent prognostic factor impacting the OS.

CONCLUSIONS

The treatment protocols need to be tailored based on further refine the stratification of ETV6::RUNX1 patients. Platelet count is an adverse independent prognostic factor. Splenomegaly and aberrant CD33 expression are associated with shorter DFS.