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t(8;21)(q22;q22) in Blast Phase of Chronic Myelogenous Leukemia

C. Cameron Yin MD, PhD, L. Jeffrey Medeiros MD, Armand B. Glassman MD, Pei Lin MD
DOI: http://dx.doi.org/10.1309/H8JH6L094B9U3HGT 836-842 First published online: 1 June 2004


The blast phase of chronic myelogenous leukemia (CML) frequently is associated with cytogenetic evidence of clonal evolution, defined as chromosomal aberrations in addition to the t(9;22)(q34;q11.2). We identified the t(8;21)(q22;q22) and other cytogenetic abnormalities by conventional cytogenetics and fluorescence in situ hybridization in 2 patients with t(9;22)-positive CML at the time of blast phase. The t(8;21), which typically is associated with a distinct subtype of de novo acute myeloid leukemia (AML) carrying the <italic>aml1/eto</italic> fusion gene, was accompanied by increased bone marrow myeloblasts (33%) in case 1 and extramedullary myeloid sarcoma in case 2, suggesting its possible role in disease progression. In case 1, the leukemic cells in aspirate smears had salmon-colored cytoplasmic granules, and immunophenotypic studies showed that the blasts expressed CD19. These findings suggest that the pathologic features of blast phase CML with the t(8;21) resemble those of de novo AML with the t(8;21).

Key Words:
  • Chronic myelogenous leukemia
  • Blast phase
  • Clonal evolution
  • t(9;22)
  • t(8;21)