Characteristics of hematologic malignancies with coexisting t(9;22) and inv(16) chromosomal abnormalities

Abstract

Background: The coexistence of t(9;22)(q34;q11.2) and inv(16)(p13q22) chromosomal abnormalities is extremely uncommon, and only a small number of such cases have been reported. Here, we characterized 7 cases of hematologic malignancy exhibiting t(9;22) and inv(16) coexistence.

Methods: We reviewed the cytogenetic data for hematologic malignancies treated at the Catholic Blood and Marrow Transplantation Center between January 2004 and June 2013. We identified 7 cases exhibiting t(9;22) and inv(16) coexistence. In addition, we analyzed mutations in the IKZF1, NPM1, FLT3, N-RAS, K-RAS, c-KIT, and TP53 genes.

Results: Four cases of chronic myelogenous leukemia (CML; 1 chronic phase, 2 accelerated phase, and 1 blast phase) and 3 cases of acute myeloid leukemia (AML; 1 de novo and 2 therapy-related) were identified. The percentages of circulating blasts and bone marrow eosinophils were higher in AML cases than in CML cases (53% vs. 5% and 30% vs. 5.5%, respectively). The proportions of each chromosomal abnormality were used along with follow-up karyotyping results to identify secondary changes. In BCR/ABL, a p210 fusion transcript was associated with CML, whereas a p190 fusion transcript was associated with AML. One patient with AML harbored 2 mutations: c-KIT D816V and TP53 E11Q. All patients except 1 with CML blast phase sustained clinical remission after treatment, which included an imatinib mesylate regimen.

Conclusion: This study shows that observations of bone marrow morphology, initial and follow-up cytogenetic studies, and karyotyping of BCR/ABL1 and CBFB/MYH11 provide valuable information for characterizing hematologic malignancies exhibiting t(9;22) and inv(16) coexistence.

Keywords: Acute myeloid leukemia; BCR/ABL1; CBFB/MYH11; Chronic myelogenous leukemia; inv(16); t(9;22).