Three novel fusion transcripts of the paired box 5 gene in B-cell precursor acute lymphoblastic leukemia

PAX5 encodes for a transcription factor essential for B-lymphoid cell commitment and is rearranged in 30% of B-cell precursor acute lymphoblastic leukemia pediatric patients (BCP-ALL). Since the first characterization of PAX5/ETV6, an increasing number of PAX5 fusion genes have been described in both adult and pediatric BCP-ALL patients. As reported in our recent review, PAX5 fusion partners encode a variety of proteins involved in cell structure (ELN, POM121), transcriptional regulation (ETV6, PML, FOXP1, MLLT3), phosphorylation (JAK2), and unknown functions (C20orf112,7AUTS2). Here we report the characterization of three new PAX5 partner genes in BCP-ALL: CHFR (a novel transcript isoform), SOX5 and POM121C. Moreover, we report cases displaying PAX5/AUTS2 and PAX5/MLLT3 fusions