Schematic representation of the different molecular events during progression of CML, supporting the co-occurrence of mutated RUNX1 alleles on one chromosome 21q22 and on the derived chromosome 1p36 harboring the RUNX1-PRDM16 fusion (example of UPN 11). (A) Sequencing data of the L29S mutation. Left: DNA-sequencing electrophoregram revealing the L29S mutation at 2/3 level. Right: RNA-sequencing electrophoregram of the full RUNX1 revealing the L29S mutation at 1/2 level. (B) Scenario of genetic and chromosomal events during the disease progression. Red cross: the mutated RUNX1 allele. Green cross: the remaining 3′ region of truncated RUNX1 gene after t(1;21)(p36;q22). (C) Representation of the corresponding various alleles of RUNX1 (white open bar) and PRDM16 (gray open bar) during CML course.