T-Cell Leukemia Cell Line Harboring Previously Undescribed CBFB::MYL11 Fusion Exhibits a Genome Profile Implicating Cytoskeletal Abnormality.

INTRODUCTION: Gene fusions involving core binding factors (CBFs), such as CBFB::MYH11, are major contributing factors to leukemia development. The pathogenic mechanism is believed to lie in abnormalities in CBF, however, myosin, the fusion partner, has received little attention. In a preliminary analysis, we identified a previously undescribed fusion transcript, CBFB::MYL11, in RNA-sequencing data from the T-cell leukemia cell line HPB-ALL. We hypothesized that leukemia cells harboring CBFB::MYH11 or CBFB::MYL11 may share a common pathological mechanism involving myosin fusion. METHODS: Fluorescence in situ hybridization was performed to analyze the structure of CBFB::MYL11 and Western blotting was performed to verify the fusion protein in HPB-ALL. Differentially expressed gene (DEG) and gene ontology (GO) analyses were performed on ME-1 harboring CBFB::MYH11 and HPB-ALL to investigate characteristics of gene expression and molecular function. RESULTS: In situ amplification of MYL11 and co-amplification of CBFB and MYL11 on a marker chromosome were observed. Elevated MYH11 and MYL11 expression and significant upregulation of genes related to the cytoskeleton were observed in the ME-1 and HPB-ALL cell lines. Bands consistent with the CBFB::MYL11 fusion protein were observed using Western blotting. CONCLUSION: This study underscores the pathological significance of cytoskeletal abnormalities in leukemia with CBFB/myosin fusion and provides a foundation for further investigation into their molecular mechanisms.