RUNX1 mutations in myeloid transformation of CML. (A) Summary of the 10 types of RUNX1 mutations in CML patients with acute transformation of CML analyzed in our study. Three categories of mutations were seen: missense mutations, nonsense mutations, and frameshift mutations. Arrowheads and vertical lines indicate the sites of mutation; X represents the site of the stop codon. ES indicates the Ear-2 binding site; UTR, untranslated region. (B) Morphological and histochemical investigation of BM samples from unique patient number 2 (UPN2) with RUNX1 H78Q. (Bi) Wright staining of BM cellular smear from patient UPN2 at CML-CP. (Bii-Bv) Examination on the BM samples from patient UPN2 at CML-BC: Wright staining (Bii); MPO staining, a specific marker of myeloid cells (Biii); periodic acid-Schiff staining (Biv); and naphthol AS-chloracetate esterase staining, a marker of granulocytes (Bv).