[Clinical characteristics and genotype analysis of two rare subtypes of acute myeloid leukemia]

The clinical data of patients with acute myeloid leukemia (AML) treated at Hebei Yanda Lu Daopei Hospital between August 1, 2024, and March 1, 2025 were retrospectively included, to differentiate AML with the same recurrent t(11;12)(p15;q13) karyotype but harboring distinct rare fusion genes, namely NUP98::RARG::LINE-L2a and NUP98::HOXC13. Two patients were included: Patient 1, a 12-year-old male, visited Hebei Yanda Lu Daopei Hospital on August 8, 2024, due to "fever for 4 days accompanied by sore throat"; Patient 2, a 33-year-old female, visited the hospital on September 22, 2024, due to "recurrent fatigue and cough for over one month". Case 1 and Case 2 carried the NUP98::RARG::LINE-L2a and NUP98::HOXC13 fusion genes, respectively. The patient with NUP98::RARG::LINE-L2a fusion genes exhibited bone marrow morphology and immunophenotypic features resembling acute promyelocytic leukemia (APL) but was resistant to all-trans retinoic acid. Although initial treatment achieved remission, early relapse occurred. The patient with NUP98::HOXC13 fusion genes showed increased myeloblasts, the presence of Auer rods, and an elevated proportion of promyelocytes, along with mutations in FLT3-TKD gene, RUNX1 gene and, WT1 gene, demonstrating resistance to multiple chemotherapy regimens. Both patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) without achieving complete remission. After transplantation, they were followed for 8 and 9 months, respectively, with quantitative monitoring of fusion genes showing negative results. Although the patients with NUP98::RARG::LINE-L2a and NUP98::HOXC13 fusion genes have completely identical chromosomal abnormalities, but they are different rare molecular subtypes. Both involve the NUP98 gene. The former partner gene is RARG, with clinical manifestations, bone marrow morphology, and immunophenotype similar to APL. The latter partner gene is HOXC13, with the characteristics of NUP98-AML patients.