Publicly available chromatin accessibility data generated by Assay for Transposase-Accessible Chromatin using sequencing (ATAC-Seq) in two small cohorts of B-cells from CLL patients [16, 19] indicated that the genomic regulatory regions upstream of exons 1c and 1b lie in an open chromatin state, supporting that active transcription is ongoing at these alternative UGT2B17 exons in CLL patient’s cells of both M-CLL and UM-CLL prognostic subgroups (Fig. 1B; Fig. S1 and Fig. S2, Supplementary file 1). This evidence concerns the gene UGT2B17 and B-cell chronic lymphocytic leukemia.