Translocation (6;9;22)(p25;q34;q11.2) identified by FISH in acute leukemia

A complex karyotype involving chromosomes 3, 6, 11, 12, and 22 in adult acute lymphoblastic leukemia

Complex chromosomal abnormalities are rare in adult patients with acute lymphoblastic leukemia (ALL). Using molecular methods, we characterized a complex karyotype involving chromosomes 3, 6, 11, 12, and 22 in a 38-year-old man with ALL. Cytogenetic analysis revealed the following karyotype: 46,XY,der(3)t(3;?6)(q22;?p21), - 6,add(11)(q23),add(12)(p13), + mar[10]/46,XY[19]. Because patients with 11q23 abnormalities have a poor prognosis and require aggressive treatment, we used fluorescence in situ hybridization (FISH) to fully characterize the abnormalities. FISH analysis showed no rearrangement of the MLL or ETV6-CBFA2 (TEL-AML1) genes; the wild-type ETV6 allele was deleted in most cells. The revised karyotype after the FISH analysis was as follows: 46,XY,der(3)t(3;12)(p13;p?13)del(3)(q21),der(6)inv(6)(p21q21)ins(6;3)(q21;q21q25),der(11)t (3; 11)(q25;q23),der(12)t(11; 12)(q23;p?12),t(12;22)(p13;q13). Although structural abnormalities involving 11q23 and 12p13 bands were identified by conventional cytogenetics, this report clearly demonstrates that molecular assays are needed to fully characterize gene rearrangements, complex translocations as well as to assign patients to the appropriate treatment group.

Amplification of BCR-ABL rearrangement in atypical Philadelphia chromosome: a new variant detected by fluorescence in situ hybridization in one case of acute lymphoblastic leukemia

We report on a 67-year-old woman with acute lymphoblastic leukemia (ALL) who was supposed to have a variant Philadelphia (Ph) translocation identified by conventional cytogenetic techniques. Fluorescence in situ hybridization (FISH) analysis demonstrated the presence of an amplification of BCR-ABL rearrangement at locus 22q11. This is the first observation, to our knowledge, of a duplicated BCR-ABL chimeric gene within the derived chromosome 22 in ALL. Our observation supports the possibility of detecting a variant Ph chromosome at the single-cell level by FISH analysis.