Cytogenetic and fluorescence in situ hybridization analyses of the patient. The bone marrow cells were cultured for 24 h and were analyzed for karyotyping and fluorescence in situ hybridization (FISH) with standard procedures. Clonal karyotypic abnormalities were described according to the International System for Human Cytogenetic Nomenclature (ISCN, 2009). A) Karyotype was analyzed on R-banded metaphases showing a t(5;21)(q21;q22), suggesting the involvement of the RUNX1 gene located at 21q22. B) FISH analysis of the rearrangement of RUNX1 by using BAC probes RP11-177 L11 (red) and RP11-77I17 (green).The separated red and green signals indicated a translocation involving RUNX1 gene.