A novel three-colour fluorescence in situ hybridization approach for the detection of t(7;12)(q36;p13) in acute myeloid leukaemia reveals new cryptic three way translocation t(7;12;16)

© 2013 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).The t(7;12)(q36;p13) translocation is a recurrent chromosome abnormality that involves the ETV6 gene on chromosome 12 and has been identified in 20–30% of infant patients with acute myeloid leukaemia (AML). The detection of t(7;12) rearrangements relies on the use of fluorescence in situ hybridization (FISH) because this translocation is hardly visible by chromosome banding methods. Furthermore, a fusion transcript HLXB9-ETV6 is found in approximately 50% of t(7;12) cases, making the reverse transcription PCR approach not an ideal screening method. Considering the report of few cases of variant translocations harbouring a cryptic t(7;12) rearrangement, we believe that the actual incidence of this abnormality is higher than reported to date. The clinical outcome of t(7;12) patients is believed to be poor, therefore an early and accurate diagnosis is important in the clinical management and treatment. In this study, we have designed and tested a novel three-colour FISH approach that enabled us not only to confirm the presence of the t(7;12) in a number of patients studied previously, but also to identify a cryptic t(7;12) as part of a complex rearrangement. This new approach has proven to be an efficient and reliable method to be used in the diagnostic setting

T(6;9)(p22;q34)/DEK-NUP214-rearranged pediatric myeloid leukemia: An international study of 62 patients

Acute myeloid leukemia with t(6;9)(p22;q34) is listed as a distinct entity in the 2008 World Health Organization classification, but little is known about the clinical implications of t(6;9)-positive myeloid leukemia in children. This international multicenter study presents the clinical and genetic characteristics of 62 pediatric patients with t(6;9)/DEK-NUP214-rearranged myeloid leukemia; 54 diagnosed as having acute myeloid leukemia, representing <1% of all childhood acute myeloid leukemia, and eight as having myelodysplastic syndrome. The t(6;9)/DEK-NUP214 was associated with relatively late onset (median age 10.4 years), male predominance (sex ratio 1.7), French-American-British M2 classification (54%), myelodysplasia (100%), and FLT3-ITD (42%). Outcome was substantially better than previously reported with a 5-year event-free survival of 32%, 5-year overall survival of 53%, and a 5-year cumulative incidence of relapse of 57%. Hematopoietic stem cell transplantation in first complete remission improved the 5-year event-free survival compared with chemotherapy alone (68% versus 18%; P<0.01) but not the overall survival (68% versus 54%; P=0.48). The presence of FLT3-ITD had a non-significant negative effect on 5-year overall survival compared with non-mutated cases (22% versus 62%; P=0.13). Gene expression profiling showed a unique signature characterized by significantly higher expression of EYA3, SESN1, PRDM2/RIZ, and HIST2H4 genes. In conclusion, t(6;9)/DEK-NUP214 represents a unique subtype of acute myeloid leukemia with a high risk of relapse, high frequency of FLT3-ITD, and a specific gene expression signature

Proposals for standardized Protocols for cytogenetic analyses of acute leukemias, chronic lymphocytic leukemia, chronic myeloid leukemia, chronic myeloproliferative disorders, and myelodysplastic syndromes

The impact of cytogenetic characterization based on chromosome banding analyses and fluorescence in situ hybridization on clinical decision making has increased dramatically during recent years. Therefore, laboratory techniques have to be optimized to provide reliable results for optimal patient care. In addition, quick and correct results save time and money by preventing unnecessary additional diagnostics and suboptimal treatment approaches. It was our aim to present proposals for standardized protocols to improve the diagnosis, and hence the treatment outcome, of hematologic malignancies

Lack of expression of the chondroitin sulphate proteoglycan neuron-glial antigen 2 on candidate stem cell populations in paediatric acute myeloid leukaemia/abn(11q23) and acute lymphoblastic leukaemia/t(4;11)

textabstractIt has increasingly been acknowledged that only a few leukaemic cells possess the capability to renew themselves and that only these self-renewing leukaemic stem cells are able to initiate relapses. Therefore, these leukaemic stem cells should be the target cells for therapy and for minimal residual disease (MRD) detection. Because of its presence on blasts of 11q23-rearranged high-risk leukaemic patients, neuron-glial antigen 2 (NG2) is thought to be a valuable marker for detecting leukaemic stem cells. Six acute myeloid leukaemia (AML)/abn(11q23) and three acute lymphoblastic leukaemia (ALL)/t(4;11) samples were analysed by four-colour flow cytometry for NG2 expression on primitive cell populations. Candidate leukaemic cell populations were defined by the antigen profiles CD34+CD38- in AML and CD34+CD19 -CD117+ in ALL. Surprisingly, in all patients these candidate stem cell populations were shown to lack expression of NG2. Instead, a correlation between the expression of the myeloid differentiation marker CD33 and increasing levels of NG2 on maturing cells could be demonstrated. Similarly, in ALL patients CD34+CD19+ cells showed a higher expression of NG2 mRNA compared with CD34+CD19-. Thus, NG2 appears to be upregulated with differentiation and not to be expressed on primitive disease-maintaining cells. This hampers the clinical use of NG2 as a therapeutic target and as a sensitive marker for MRD detection