A Ph-negative chronic myeloid leukemia with a complex BCR/ABL rearrangement and a t(6;9)(p21;q34.1)

Chronic myeloid leukemia (CML) is a clonal malignant disorder of a pluripotent hematopoetic stem cell characterized by the presence of the Philadelphia (Ph) chromosome in more than 90% of patients. Cryptic or masked BCR/ABL gene rearrangements may be found in cases with a normal karyotype and in cases with the complex karyotype, in which typical t(9;22) is not visible at the microscopic level. Those rearrangements can now be detected by fluorescence in situ hybridization. Here, we report on a novel and complex Ph chromosome-negative CML case with a t(6;9) (p21;q34.1) in which the BCR/ABL fusion gene is located at 6p21. (c) 2006 Elsevier Inc. All rights reserved

t(5;6;12 ) associated with resistance to imatinib mesylate in chronic myeloid leukemia

A patient with t(9;22)-positive chronic myelogenous leukemia (CML) developed a resistance to therapy with imatinib mesylate (Glivec) which coincided with the appearance of t(5;6;12) in the same cells with t(9;22) [46,XX,t(5;6;12)(q14?;q21?;q23?),t(9;22)(q34;q11)]. She remains in a continuous chronic phase of CML. This is the first reported instance of karyotype evolution temporally associated, and possibly involved, with the induction of resistance to imatinib mesylate but without any signs of evolution of leukemia toward a more anaplastic and aggressive form