Efficacy Analysis of Allogeneic Hematopoietic Stem Cell Transplantation for Myeloid/Lymphoid Neoplasms with Eosinophilia and Tyrosine Kinase Gene Fusions

Abstract Objective To investigate the clinical characteristics, diagnostic features, treatment strategies and prognosis of patients with myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK). Methods Clinical data of 13 patients diagnosed with MLN-TK from January 2013 to October 2024 were retrospectively analyzed. Results A total of 13 patients were enrolled, including 12 males and 1 female, with a median age of 42 years (range, 6–59 years). The initial diagnoses comprised 4 cases of acute lymphoblastic leukemia (ALL), 4 cases of myeloproliferative neoplasms (MPN), 2 cases of myelodysplastic syndromes (MDS), 2 cases of acute myeloid leukemia (AML), and 1 case of mixed-phenotype acute leukemia (MPAL). Genetic detection identified FGFR1 rearrangement in 6 cases, PDGFRA rearrangement in 3 cases, PDGFRB rearrangement in 2 cases, JAK2 rearrangement in 1 case, and ETV6::ABL1 fusion in 1 case. Eight patients (61.5%) were complicated with eosinophilia, and 5 patients (38.4%) had extramedullary disease involvement. All patients were followed up until September 2025. Six patients received allogeneic hematopoietic stem cell transplantation (Allo-HSCT), among whom 5 survived and 1 died of severe acute graft-versus-host disease. The 5-year overall survival rate of transplanted patients was 83.3%. Among the 7 patients who did not undergo transplantation, 4 died of primary disease relapse and 3 were lost to follow-up. Conclusion MLN-TK is highly heterogeneous and easily misdiagnosed or missed. Tyrosine kinase inhibitor can be used as an effective bridging therapy. However, most subtypes except PDGFRA-rearranged neoplasms cannot achieve durable therapeutic responses. Allo-HSCT is the core curative approach for long-term survival of MLN-TK patients.