Reciprocal reading by long-distance inverse PCR also disclosed KMT2A fusions with PITPNA in one patient, with LOC100132273 in another patient, and with DNA sequences not compatible with any gene in three patients. <...> The most common KMT2A breakpoint region was intron/exon 9 (3/8 patients), followed by intron/exon 11 and 10. <...> Finally, multicolor banding revealed breakpoints in other chromosomes whose biological and prognostic implications remain to be determined. <...> We conclude that the combination of molecular techniques used in this study can efficiently identify KMT2A fusion partners in complex pediatric acute leukemia karyotypes. <...> COMPARATIVE ANALYSIS OF INDIVIDUAL CHROMOSOME INVOLVEMENT IN MICRONUCLEI INDUCED BY MITOMYCIN C AND BLEOMYCIN IN HUMAN LEUKOCYTES Hovhannisyan G.1 Harutyunyan T.1 , Aroutiounian R.1 , Liehr T.3 , Babayan N.1,2 1Department of Genetics and Cytology, Faculty of Biology, Yerevan State University, Yerevan, Armenia; 2 Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia; 3 Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Jena, Germany Micronucleus (MN) assay is a well standardized approach for evaluation of clastogenic/aneugenic effects of mutagens. <...> Fluorescence in situ hybridization (FISH) is successfully used to characterize the chromosomal content of MN. <...> However, the relationships between nuclear positioning, length, and gene density of individual chromosomes and their involvement in MN induced by different mutagens have not been clearly defined. <...> Chromosomal content of MN was characterized in human leukocytes treated with mitomycin C (MMC) and bleomycin (BLM) by FISH using centromeric (cep) and whole-chromosome painting (wcp) probes. <...> Involvement of chromosomes 8, 15 and 20 in MMC-induced and chromosomes 1, 9 and 16 in BLM-induced MN was studied, and correlated with chromosome size, gene density and interphase position. <...> The results obtained were analyzed together with previous own data on the frequencies of inclusion of chromosomes 3, 4, 6, 7, 9, 16, 17, 18, and X in MMC-induced MN. <...> It could be shown that MMC- and BLM-induced MN could contain material derived from all chromosomes investigated. <...> Involvement of whole chromosomes 8, 15 <...>