Fig. 1

a) G-banded karyotype bone marrow cells at leukemic transformation showed ins(6;22)(q23.3;q11) and der(22q) (black arrows). b) Metaphase FISH experiment with Whole Chromosome Paint (WCP) 6 (Texas Red) and WCP 22 (FITC). Genomic material of chromosome 22 was present on der(6) and der(9) long arms. c) Schema of clones RP1-32B1 (MYB) (Spectrum Orange) and RP11-367E7 (EWSR1) (Spectrum Green) and their mapping. Normal and derivative chromosomes 6 and 22 hybridization patterns; a green/orange fusion signal was present on der(6). A fusion signal was found in interphase nuclei (yellow arrow). d) SNPa analysis detected loss at 22q (red triangle) in BM sample at leukemic transformation. e) Schema of the EWSR1-MYB fusion gene and putative protein. f) MYB expression analysis in four combined cases at chronic phase and leukemic transformation and in a positive control group (4 RUNX1-RUNX1T1 AML, 4 MLL-positive AML, and 4 BCR-ABL1-positive B-cell ALL). g) Longitudinal expression of MYB and BCL2 in the index case. Data are reported for one representative of three independent experiments. Abbreviations: der, derivative chromosome; nl, normal; TAD, transcriptional-activating domain; R1, R2, R3, imperfect aminoacidic repeats; NRD, negative regulatory domain; CP, chronic phase; LT, leukemic transformation; wt, wild-type; R, relapse