[Acute megakaryoblastic leukemia with CBFA2T3::GLIS2 fusion gene: 3 cases report and literature review]

This study retrospectively analyzed the clinical manifestations, genetic characteristics, treatment courses, and prognoses of patients with pediatric acute megakaryoblastic leukemia (AMKL) with CBFA2T3::GLIS2 fusion treated at the Institute of Hematology, Chinese Academy of Medical Sciences. Further, the diagnostic and therapeutic features of this rare AMKL subtype, in conjunction with domestic and international literature, were summarized. The patients comprised one male and two females, with a median age at onset of 16 months (range, 8-19 months). Central nervous system leukemia was present at diagnosis in two cases. All were classified as acute myeloid leukemia (AML) -M(7) according to the French-American-British classification, with immunophenotypes demonstrating CD56 positivity and human leukocyte antigen-DR negativity. All patients showed complex abnormal karyotypes, including trisomy 21 in two cases. All patients achieved morphological complete remission (CR) after chemotherapy. However, all patients experienced early relapse, with a median relapse time of 11 months (range, 7-13 months), and the median overall survival time was 16 months (range, 15-47 months). One patient relapsed after the first hematopoietic stem cell transplantation and relapsed again after a second transplantation and is currently receiving palliative care. The other two patients discontinued treatment after relapse and subsequently died. These results reveal that CBFA2T3::GLIS2 fusion-positive AMKL is a highly aggressive subtype, frequently associated with a CD56-positive, HLA-DR-negative immunophenotype, and complex karyotypes, with trisomy 21 observed in a subset of cases. This subtype is characterized by a high relapse rate and an extremely poor prognosis. At present, effective therapeutic approaches are lacking, with an urgent need to explore novel treatment strategies to improve clinical outcomes.