Performances of Targeted RNA Sequencing for the Analysis of Fusion Transcripts, Gene Mutation, and Expression in Hematological Malignancies.

RNA sequencing holds great promise to improve the diagnostic of hematological malignancies, because this technique enables to detect fusion transcripts, to look for somatic mutations in oncogenes, and to capture transcriptomic signatures of nosological entities. However, the analytical performances of targeted RNA sequencing have not been extensively described in diagnostic samples. Using a targeted panel of 1385 cancer-related genes in a series of 100 diagnosis samples and 8 controls, we detected all the already known fusion transcripts and also discovered unknown and/or unsuspected fusion transcripts in 12 samples.

Exome sequencing identifies recurrent alterations and the absence of , and mutations in splenic diffuse red pulp small B-cell lymphoma.

Splenic diffuse red pulp lymphoma is an indolent small B-cell lymphoma recognized as a provisional entity in the World Health Organization 2008 classification. Its precise relationship to other related splenic B-cell lymphomas with frequent leukemic involvement or other lymphoproliferative disorders remains undetermined. We performed whole-exome sequencing to explore the genetic landscape of ten cases of splenic diffuse red pulp lymphoma using paired tumor and normal samples.

Splenic diffuse red pulp lymphoma has a distinct pattern of somatic mutations amongst B-cell malignancies.

Splenic Diffuse Red Pulp Lymphoma (SDRPL) has been recently introduced as a provisional entity but differential diagnosis with other splenic lymphomas is needed to be clarified since the therapeutic approaches are distinct. Recently described recurrent mutations or CD180 expression appear useful for differential diagnosis. We completed our previous description in a larger cohort including 53 patients selected on the presence of characteristic villous cells in peripheral blood (PB) and a specific immunophenotype.

Molecular characterization and follow-up of five CML patients with new BCR-ABL1 fusion transcripts.

We report five chronic myeloid leukaemia (CML) patients in whom we identified and characterized undescribed BCR-ABL1 fusion transcripts. We investigated the precise features of the molecular rearrangements and the minimal residual disease follow-up for these five patients. Three resulted from new rearrangements between the BCR and ABL1 sequences (the breakpoints being located within BCR exon 13 in two cases and within BCR exon 18 in one case).

New Quantitative Method to Identify NPM1 Mutations in Acute Myeloid Leukaemia.

Somatic mutations in the NPM1 gene, which encodes for nucleophosmin, have been reported to be the most frequent genetic abnormalities found in acute myeloid leukaemia (AML). Their identification and quantification remain crucial for the patients' residual disease monitoring. We investigated a new method that could represent a novel reliable alternative to sequencing for its identification.

High DNA methyltransferase DNMT3B levels: a poor prognostic marker in acute myeloid leukemia.

It has been recently shown that DNA methyl transferase overexpression is correlated with unfavourable prognosis in human malignancies while methylation deregulation remains a hallmark that defines acute myeloid leukemia (AML). The oncogenic transcription factor EVI1 is involved in methylation deregulation and its overexpression plays a major role for predicting an adverse outcome. Moreover, the identification of DNMT3A mutations in AML patients has recently been described as a poor prognostic indicator.

The durable clearance of the T315I BCR-ABL mutated clone in chronic phase chronic myelogenous leukemia patients on omacetaxine allows tyrosine kinase inhibitor rechallenge.

Purpose: The onset of a BCR-ABLT315I mutation during the course of chronic myelogenous leukemia (CML) on tyrosine kinase inhibitors (TKIs) usually results in poor survival, and therapeutic options remain few in the absence of any allogeneic donor.

Patients And Methods: We have investigated the affect of subcutaneous omacetaxine (OMA, or homo-harringtonine) cycles on unmutated and T315I-mutated BCR-ABL transcripts in a series of 8 TKI-resistant chronic-phase CML patients and we have addressed the question of whether the administration of OMA could resensitize patients to TKIs. Patients were regularly monitored for total disease burden and for BCR-ABLT315I transcripts using a new quantitative sensitive technique (sensitivity threshold, 0.

Longitudinal studies of SRC family kinases in imatinib- and dasatinib-resistant chronic myelogenous leukemia patients.

This report aims to more accurately define the frequency of the involvement of SRC Family Kinases (SFKs) in imatinib- and dasatinib-resistant CML patients. Clinical samples were analysed during in vivo treatment. We confirmed the high frequency of SFKs involvement in Tyrosine kinase inhibitor-resistant CML (52% of the cases) and even further in progressive disease and blast crises (60% of the cases).

Pegylated IFN-α2a combined to imatinib mesylate 600mg daily can induce complete cytogenetic and molecular responses in a subset of chronic phase CML patients refractory to IFN alone or to imatinib 600mg daily alone.

This phase I/II study was designed to demonstrate the tolerance and the efficacy of a combination of pegylated interferon-α 2a to Imatinib mesylate (IM) 600mg daily in cytogenetically IM-resistant but in CHR chronic phase CML patients. The combination was generally well tolerated in the 15 evaluable patients. A significant reduction of the Ph1(+) BM metaphases was observed in these poor prognosis patients, with 2 long-term CCyR including 2 MMR.

BCR-ABL mutant kinetics in CML patients treated with dasatinib.

Dasatinib is efficient in vitro against most of CML cells harboring ABL kinase domain mutations and induces high rates of response in imatinib-resistant CML patients. Here, we monitored the mutated BCR-ABL transcripts during the follow-up of 12 CML patients treated with dasatinib. We identified four groups of patients based on their sensitivity to dasatinib.

The role of the K247R substitution in the ABL tyrosine kinase domain in sensitivity to imatinib.

Imatinib mesylate has become the gold standard front-line treatment of chronic myelogenous leukemia through its ability to inhibit ABL tyrosine kinase. Resistance to this inhibition may occur. We investigated the role of the K247R polymorphism in persistent sensitivity.