Translocation between chromosome 5q35 and chromosome 11q13-- an unusual cytogenetic finding in a primary refractory acute myeloid leukemia.

Cytogenetic abnormalities are observed in approximately two-thirds of patients with acute myeloid leukemia (AML). Chromosome rearrangements are associated with specific subtypes of AML and associated prognosis. We report a patient with AML, M2, who was primarily refractory to standard induction chemotherapy with idarubicin and cytarabine. Flow cytometry of a bone marrow aspirate showed aberrant expression of B-cell markers including CD19. Cytogenetic studies disclosed a translocation between 5q35 and 11q13. Fluorescence in situ hybridization analyses demonstrated that neither the NSD1 nor MLL genes were involved in this case. Further study is required to define conclusively the genes involved and their contribution to pathogenesis in this case.