Abstract Haploidentical bone marrow transplantation combined with donor peripheral blood stem cell transplantation is an effective treatment for pediatric acute myeloid leukemia (AML). However, studies on differential protein expression and biological behavior changes following stem cell transplant failure-especially in cases where an A-type father donates stem cells to his O-blood type daughter with AML-M2 are rare. Furthermore, research on the bioinformatic characteristics and survival prediction of pediatric AML patients remains scarce. To address this gap, we utilized the GTEx and TCGA databases to perform an in-depth analysis of the disease characteristics and survival predictions in pediatric AML. Additionally, proteomic sequencing and validation were conducted on a specific case involving an A-blood type father donating haploidentical bone marrow and stem cells to his O-blood type daughter with AML-M2, who subsequently experienced transplant relapse. This study aims to provide a comprehensive understanding of the bioinformatic characteristics of pediatric AML and, through the unique perspective of this relapse case, explore the changes in protein expression. These findings offer valuable insights into the mechanisms of disease progression, optimizing treatment strategies, and preventing transplant failure in similar cases.

The U2 small nuclear RNA auxiliary factor1（U2AF1）belongs to the splicing factor SR family. This spliceosome involves in intron removal from messenger RNAs (mRNAs) and exon-exon binding. Nevertheless, the mutation of U2AF1 is associated with myelodysplastic syndrome (MDS), bone marrow cancer, and solid tumors, including lung cancer, pancreatic carcinoma, and other malignant tumors. Besides, the expression and mutation of U2AF1 will promote the occurrence or prognosis of relevant diseases. Hence, targeted therapies are required in the treatment of relevant diseases.Unfortunately, it remains unclear about the role of U2AF1 in different diseases. Therefore, we summarized the pathogenic mechanism of U2AF1 in different malignant diseases and related targeted agents.