EVI1 overexpression in t(3;17) positive myeloid malignancies results from juxtaposition of EVI1 to the MSI2 locus at 17q22

Chromosomal translocations involving the EVI1 locus are a recurrent finding in myeloid leukemia and are associated with poor prognosis. In this study, we performed a detailed molecular characterization of the recurrent translocation t(3;17)(q26;q22) in 13 hematologic malignancies. The EVI1 gene locus was rearranged in all 13 patients and was associated with EVI1 overexpression. In 9 out of 13 patients, the 17q breakpoints clustered in a 250 kb region on band 17q22 encompassing the MSI2 (musashi homologue 2) gene. Expression analyses failed to demonstrate ectopic MSI2 expression or the presence of an MSI2/EVI1 fusion gene. In conclusion, we show for the first time that the t(3;17) is indeed a recurrent chromosomal aberration in myeloid malignancies. In keeping with findings in other recurrent 3q26 rearrangements, overexpression of the EVI1 gene appears to be the major contributor to leukemogenesis in patients with a t(3; 17)

EVI1 activation in blast crisis CML due to juxtaposition to the rare 17q22 partner region as part of a 4-way variant translocation t(9;22)

<p>Abstract</p> <p>Background</p> <p>Variant translocations t(9;22) occur in 5 to 10% of newly diagnosed CMLs and additional genetic changes are present in 60–80% of patients in blast crisis (BC). Here, we report on a CML patient in blast crisis presenting with a four-way variant t(9;22) rearrangement involving the <it>EVI1 </it>locus.</p> <p>Methods</p> <p>Dual-colour Fluorescence In Situ Hybridisation was performed to unravel the different cytogenetic aberrations. Expression levels of <it>EVI1 </it>and <it>BCR/ABL1 </it>were investigated using real-time quantitative RT-PCR.</p> <p>Results</p> <p>In this paper we identified a patient with a complex 4-way t(3;9;17;22) which, in addition to <it>BCR/ABL1 </it>gene fusion, also resulted in <it>EVI1 </it>rearrangement and overexpression.</p> <p>Conclusion</p> <p>This report illustrates how a variant t(9;22) translocation can specifically target a second oncogene most likely contributing to the more aggressive phenotype of the disease. Molecular analysis of such variants is thus warranted to understand the phenotypic consequences and to open the way for combined molecular therapies in order to tackle the secondary oncogenic effect which is unresponsive to imatinib treatment.</p

Clinical, cytogenetic and molecular characteristics of 14 T-ALL patients carrying the TCRβ-HOXA rearrangement: A study of the Groupe Francophone de Cytogénétique Hématologique

Recently, we and others described a new chromosomal rearrangement, that is, inv(7)(p15q34) and t(7;7)(p15;q34) involving the T-cell receptor beta (TCRβ) (7q34) and the HOXA gene locus (7p15) in 5% of T-cell acute lymphoblastic leukemia (T-ALL) patients leading to transcriptional activation of especially HOXA10. To further address the clinical, immunophenotypical and molecular genetic findings of this chromosomal aberration, we studied 330 additional T-ALLs. This revealed TCRβ-HOXA rearrangements in five additional patients, which brings the total to 14 cases in 424 patients (3.3%). Real-time quantitative PCR analysis for HOXA10 gene expression was performed in 170 T-ALL patients and detected HOXA10 overexpression in 25.2% of cases including all the cases with a TCRβ-HOXA rearrangement (8.2%). In contrast, expression of the short HOXA10 transcript, HOXA10b, was almost exclusively found in the TCRβ-HOXA rearranged cases, suggesting a specific role for the HOXA10b short transcript in TCRβ-HOXA-mediated oncogenesis. Other molecular and/or cytogenetic aberrations frequently found in subtypes of T-ALL (SIL-TAL1, CALM-AF10, HOX11, HOX11L2) were not detected in the TCRβ-HOXA rearranged cases except for deletion 9p21 and NOTCH1 activating mutations, which were present in 64 and 67%, respectively. In conclusion, this study defines TCRβ-HOXA rearranged T-ALLs as a distinct cytogenetic subgroup by clinical, immunophenotypical and molecular genetic characteristics.0SCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Evaluation of four hemoglobin separation analyzers for hemoglobinopathy diagnosis

BackgroundFour automated hemoglobin separation devices are compared in their ability to detect hemoglobinopathies, both in HbA1c and in hemoglobinopathy mode. MethodsQuality control material and 58 samples, including one heterozygous -thalassemia sample, six heterozygote -thalassemia samples and 32 samples with a known hemoglobin variant, were used to assess imprecision of HbF and HbA2 measurements, correlation with the gold standard and sensitivity for detecting -thalassemia and Hb variants on D-100 (Bio-Rad Laboratories), HA 8180T (Menarini), HLC-723G8 (Tosoh Bioscience) and Capillarys 2 Flex Piercing (Sebia). ResultsImprecision was <10% for both HbF and HbA2 in all modes of all analyzers. Correlation studies for HbF and HbA2 demonstrated statistically significant but small biases when compared to the gold standard. All six -thalassemia samples but one were detected on all analyzers using a HbA2 cut-off value of 3.5%. D-100, HA8180T and the Hb-pathy mode of the HLC-723G8 and the Capillarys are able to detect the most common important Hb variants (Hb C, D, E and S), but more seldom variants can be missed as they co-elute with HbA0. The HbA1c mode of the Capillarys correctly detected all measured hemoglobin variants and can therefore be used as a hemoglobinopathy screening device. This was also the case for the most common important Hb variants on the HbA1c mode of the HLC-723G8, but two rare variants were not detected. ConclusionThis study stresses the importance for individual laboratories to know the advantages and drawbacks of their hemoglobin separation analyzer and its different modes in the diagnosis of hemoglobinopathies

Performance assessment of the Devyser high-throughput sequencing-based assay for chimerism monitoring in patients after allogeneic hematopoietic stem cell transplantation

Chimerism analysis is widely used to aid in the clinical management of patients after allogeneic hematopoietic stem cell transplantation. Many laboratories currently use assays based on PCR followed by capillary electrophoresis, with a limit of quantification of 1% to 5%. Assays with a lower limit of quantification could allow for earlier relapse detection, resulting in improved patient care. This study investigated the analytical, clinical, technical, and practical performance of the Devyser next-generation sequencing chimerism assay, a commercial high-throughput sequencing-based assay for chimerism analysis. Performance of this assay was compared with that of the Promega PowerPlex 16 HS assay, a commercial capillary electrophoresis-based assay. A limit of quantification of 0.1% was achievable with the Devyser assay. The repeatability, reproducibility, trueness, and linearity of the Devyser assay were acceptable. The Devyser assay showed potential for earlier relapse detection compared with the Promega assay. Conclusive analysis was not possible for 3% of donor-recipient pairs with the Devyser assay due to an insufficient number of informative markers; this factor was not an issue for the Promega assay. Further improvements in assay design or data analysis may allow the assay's applicability to be extended to all donor-recipient pairs studied. Technical performance criteria for chimerism analysis by high-throughput sequencing were suggested and evaluated. Both assays were found to be practical for use in a clinical diagnostics laboratory. (J Mol Diagn 2021, 23: 1116-1126; https://doi.org/10.1016

Biclonal biphenotypical B-cell lymphocytosis: a CLL in disguise?

We report a rare case of biclonal biphenotypic B-cell lymphocytosis with chronic lymphocytic leukaemia phenotype. Clonality was initially misjudged by immunophenotyping because of its polyphenotypic pattern. Polymerase chain reaction analysis revealed clonality of the immunoglobulin heavy chain and kappa light chain gene rearrangement, indicating the presence of a monoclonal B-lymphocyte population. Immunophenotyping was repeated after cell sorting and revealed two CD5+CD19+ populations with different light chain restriction. Different genetic abnormalities for both clones, as evidenced by fluorescence in situ hybridisation and hypermutation analysis, support the diagnosis of two independently originated but co-existing B-cell clones. This case illustrates the importance of using multiple techniques in the diagnostic work-up of haematological malignancies