[A case of t(3;3)(q21;q26.2) associated with severe multilineage dysplasia and multi-drug resistance in blastic crisis of chronic myelogenous leukemia].

The t(3;3)(q21;q26.2) is known to be mainly observed in hematologic myeloid malignancies, as a form of 3q21q26 syndrome. Cytogenetic abnormalities of 3q21q26 syndrome result in RPN1-EVI1 fusion transcripts involving ecotropic viral integration site-1 (EVI1) at 3q26.2 and ribophorin I (RPN1) at 3q21, and the fusion transcripts play an important role in leukemogenesis and disease progression. They are usually associated with dysplasia, especially of megakaryocytes. Patients with these cytogenetic abnormalities show extremely poor prognosis even with aggressive anti-leukemic therapy. We report a case of blastic crisis of CML with both t(3;3)(q21;q26.2) and t(9;22)(q34;q11.2) and associated severe multilineage dysplasia. The patient showed a poor response to imatinib, dasatinib and aggressive induction therapy. When both t(3;3)(q21;q26.2) and t(9;22)(q34;q11.2) are observed in cases of leukemia with increased blasts, they are best considered as aggressive phases of CML with t(3;3)(q21;q26.2), rather than AML with t(9;22)(q34;q11.2) by 2008 WHO classification.