A rare FBXO25-SEPT14 fusion in a patient with chronic myeloid leukemia treatment to tyrosine kinase inhibitors: a case report

Objectives Exploring the pathogenesis of resistance to tyrosine kinase inhibitors in patients with chronic myeloid leukemia.Case presentation This case report describes a rare fusion of FBXO25 and SEPT14 genes in a 58-year-old male patient with chronic myeloid leukemia. The patient had been treated with tyrosine kinase inhibitors for one year. After 6 months of imatinib treatment, the patient's symptoms improved significantly and the complete blood count returned to normal, but the optimal ratio of BCR::ABL transcripts to ABL transcripts is greater than 10 % indicating treatment failure. Then we switched to a second generation TKIs to continue treatment, During the Flumatinib treatment period, the patient developed severe bone marrow suppression and exhibited additional cytogenetic abnormalities involving chromosome aberration: 47, XY,+8[5]/47, idem, inv(Y)(p11.2q11.23)[15]. By adjusting the drug dose and elevating blood cells, the patient's BCR::ABL P210/ABL was 2.56 % after six months of Flumatinib treatment. The patient's BCR::ABL P210/ABL consistently remained above 1 % throughout the treatment, and additional cytogenetic abnormalities were present. Next-generation sequencing revealed the recombination of exon 4 of the FBXO25 and exon 10 of the SEPT14, and this mutation has not been previously reported.Conclusions Our findings suggest that the FBXO25-SEPT14 fusion may be associated with tyrosine kinase inhibitors resistance in chronic myeloid leukemia.