A Case of Concomitant Inv(3)(q21q26) and Cryptic BCR/ABL1 Rearrangement in the Blast Crisis of Chronic Myeloid Leukemia

Structural abnormalities of the long arm of chromosome 3 (3q) have been associated with elevated platelet count and hyperplasia of megakaryocytes with dysplasia in various hematological malignancies. Some cases of chronic myeloid leukemia (CML) may acquire inv(3) (q21q26) or t(3;3)(q21;q26), and such a finding usually indicates accelerated or blast phase of their disease. We report a case of concomitant inv(3) (q21q26) and cryptic BCR/ABL1 rearrangement in the blast crisis of CML. The patient was 17-year-old male and showed marked leukocytosis and thrombocytosis at admission. Leukocyte differentials showed eosinophilia, basophilia and increased blasts. The bone marrow was hypercellular with granulocytic hyperplasia, and dysmorphic megakaryocytes were frequently observed. Conventional cytogenetic analysis revealed only an inv(3)(q21q26) and no Philadelphia chromosome was observed. FISH and RT-PCR analyses confirmed cryptic BCR/ABL1 rearrangement. The patient responded poorly with imatinib and induction chemotherapy, and expired during the course of 2nd chemotherapy with increased dose of imatinib.

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 / 대한진단검사의학회지

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.

Hematologic and Clinical Features of 3q21q26 Syndrome: Extremely Poor Prognosis and Association with Central Diabetes Insipidus / 대한진단검사의학회지

BACKGROUND: 3q21q26 syndrome includes chromosomal abnormalities of inv(3)(q21q26), t(3;3) (q21;q26), and ins(3;3)(q26;q21q26). It causes hematological diseases by the leukemogenic mechanism that the enhancer of ribophorin I gene in 3q21 induces the transcription of ecotropic viral integration site-1 gene in 3q26. Recently, it has been proposed that the 3q21q26 syndrome may be preceded by diabetes insipidus (DI), particularly when combined with monosomy 7, and is a unique disease entity. METHODS: From May 2001 to June 2006, a total of 5 patients with hematologic malignancy were found to have 3q21q26 syndrome and monosomy 7. Laboratory findings, clinical data, and association with DI were investigated. RESULTS: The rearrangement type of 3q21q26 was inv(3)(q21q26) in four patients and t(3;3)(q21; q26) in one. These patients' French American British types were AML M1, M2, M4 and M7, showing evident dysmegakaryopoiesis. Aberrant antigenic expressions of CD7 and CD56 were observed. The platelet count was relatively high as AML. All the five patients were refractory or in early relapse. Patient 5 was diagnosed with AML M7 20 days after being diagnosed with DI. While DI was well controlled with oral desmopressin, leukemia was refractory to chemotherapy. CONCLUSIONS: This study supports the recent opinion that 3q21q26 syndrome with monosomy 7 combined with DI is a disease of unique characteristics. In the relation between DI and monosomy 7 or 3q21q26 syndrome, there has been no explanation about how acquired abnormality of hematopoietic cells affects production of DDAVP by neurohormonal cells in hypothalamus. The mechanism needs further study, and this research should contribute to the understanding of genetic roles in leukemia appearing in different forms.