Clinical characteristics and prognostic analysis of different fusion gene abnormalities in childhood acute lymphoblastic leukaemia

Rui Fan¹Mengmeng Zhao¹Peiling Li¹Yunjiao Tian¹Bao Liu¹Xiaojuan Zhu¹Xi Chen²Yuanfei Wang¹Yanyan Ma¹Shu-Jun Li^1*

• ¹The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
• ²Xinyang Central Hospital, Xinyang, Shaanxi Province, China

Objective: This study aimed to analyse the clinical features and prognostic significance of different fusion gene subtypes in paediatric patients with acute lymphoblastic leukaemia (ALL). Methods: Clinical data from 132 childhood patients with ALL diagnosed between 2017 and 2022 were retrospectively analysed. Patients were categorised based on fusion gene status: TEL::AML1, BCR::ABL, E2A::PBX1, MLL::AF4, SIL::TAL1, other, negative and unknown. Clinical characteristics, laboratory findings, treatment responses, minimal residual disease status and survival outcomes were compared among different fusion gene groups. Survival analyses included overall survival (OS), event-free survival (EFS) and recurrence-free survival using the Kaplan–Meier method and Cox regression models. Results: Among 132 patients, the fusion gene distribution was as follows: negative (48.5%), unknown (32.6%), TEL::AML1 (7.6%), BCR::ABL (3.8%), E2A::PBX1 (3.0%), MLL::AF4 (2.3%), other (1.5%) and SIL::TAL1 (0.8%). B-cell immunophenotype predominated (88.6%). E2A::PBX1-positive patients showed the most favourable outcomes with 100% 5-year OS and EFS. TEL::AML1-positive patients demonstrated good prednisone responses (90%), with 90% 5-year OS. BCR::ABL and MLL::AF4 cases presented with elevated white blood cell counts (median 86.9 and 96.5 × 10⁹/L, respectively), higher lactate dehydrogenase levels and inferior treatment responses. In multivariate analysis, poor prednisone response (hazard ratio [HR] = 3.41, p = 0.005) and high-risk classification (HR = 4.92, p < 0.001) were independent adverse prognostic factors for EFS. Conclusion: Fusion gene abnormalities significantly influence the clinical presentation and prognosis of childhood ALL. E2A::PBX1 and TEL::AML1 demonstrate favourable outcomes, whereas BCR::ABL, MLL::AF4 and SIL::TAL1 are associated with unfavourable prognosis. These findings provide valuable insights for risk stratification and treatment optimisation in paediatric ALL.