Concurrent translocations of MLL and CBFA2 (AMLI) genes with new partner breakpoints in a child with secondary myelodysplastic syndrome after treatment of acute lymphoblastic leukemia

The MLL gene at 11q23 is frequently disrupted by chromosomal translocations in de novo acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL), and in secondary leukemia induced by treatment with inhibitors of topoisom erase II, including the epipodophylotoxins. The CBFA2 gene at 21q22 is also frequently disrupted in de novo ALF and AML and less commonly in secondary AML, Rearrangements of MLL and CBFA2 have been described in de novo and se condary myelodysplastic syndrome (MDS), There have been no previous descrip tions of coexisting abnormalities of MLL and CBFA2 in cases of MDS or acute leukemia. We describe a patient who developed secondary MDS after chemothe rapy for hyperdiploid ALL. At the time of conversion to MDS, the patient ha d 46 chromosomes, with an 11q23/MLL translocation involving a new partner b reakpoint at 2p23 and a 21q22/CBFA2 translocation involving a new partner b reakpoint at 6p22. This report is the first to describe new partner breakpo ints at 2p23 and 6p22 for MLL and CBFA2 genes, respectively, and concurrent rearrangements of these genes in a patient with secondary MDS. Genes Chrom osomes Cancer 28:227-232, 2000. (C) 2000 Wiley-Liss, Inc.