Rearrangements involving 3q26/EVI1 and newly identified partner loci. (A-C) Schematic depictions of chromosomal rearrangements of 3 unique atypical 3q26 patient samples: ins(6;3)(q26;q21q26) in patient #HF-23, t(3;4)(q26;p15) in patient #HF-19, and t(3;7)(q26;p22) in patient #SO-20. Figures show the loci and genes that have been rearranged and brought into the vicinity of MECOM: loci with CD164 and CCDC162P (6q21) in panel A, PROM1 and CD38 (4p15) in panel B, and FBXL18, ACTB, FSCN1 and EIF2AK1 (7p22) in panel C, respectively. ChIP-seq tracks indicative for active enhancer elements, ie, H3K27ac (yellow), H3K4me3 absence (green) and P300 (red), have been obtained from the MOLM-1 myeloid cell line.¹³  Previously published ChIP-seq tracks of myeloid transcription factors FLI1, GATA2, RUNX1, LYL1, and ERG using normal CD34⁺ cells are shown³⁷  (blue). Enhancers possibly involved in EVI1 activation are indicated with a red arrow. (D) Bar plots showing skewed expression of genes that putatively donated their enhancer. The bar plots show the genes with skewed expression: CD164 (#HF-23), PROM1 (#HF-19), and FSCN1 and EIF2AK1 (#SO-20). In 2 out of 3 samples, monoallelic EVI1 expression was found (#HF-23 and #HF-19). Allele-specific EVI1 expression could not be determined in for #SO-20, since no SNPs could be detected. Asterisk (*) indicates significant differential expression between alleles (P < .05, χ² test). (E) Hockey-stick plot showing the classification of these long stretches of H3K27ac (A-C) found in the partner loci as superenhancers (based on MOLM-1 H3K27ac ChIP-seq data using the ROSE algorithm).⁴⁵