Apparently unrelated clones shown by spectral karyotyping to represent clonal evolution of cryptic t(10;11)(p13;q23) in a patient with acute monoblastic leukemia

The accurate genetic classification of acute leukemia is of the utmost clin ical importance for treatment stratification. In the present study, we repo rt on a young girl with aggressive acute monoblastic leukemia (AML) (M5b) w ith skin, lymph node, and bone marrow involvement, in whom cytogenetic anal ysis revealed three clones with different secondary chromosomal changes. Tw o clones had the secondary +8 and del(9q) aberrations, with the der(11)t(1; 11) in the second one; the third clone was apparently unrelated to the othe rs, and herd add(7)(p?21),-13,+22, Using the spectral karyotyping (SKY) tec hnique, we found that all three clones originated from a common clone that harbored the hidden primary t(10;11)(p13;q23) or ifs derivatives, suggestin g clonal evolution. The first clone had the balanced t(10;11), the second h ad its derivative, der(10)t(10;11), and the third had the other derivative, der(11)t(10;11). On fluorescence in situ hybridization (FISH), MLL gene sp litting, with translocation of ifs centromeric portion to 10p, and deletion of its telomeric portion, was demonstrated. In conclusion, the detection o f the very poor prognostic t(10;11) aberration in AML, was possible by comp lementing the traditional cytogenetic analysis with SKY and FISH. (C) 2000 Elsevier Science Inc. All rights reserved.