Hereditary predisposition to malignant myeloid hemopathies: Caution in use of saliva and guideline based on our experience

BackgroundPredisposition to myeloid malignancies is a field at the border of hematology and genetics. Knowledge in this domain has so rapidly increased that WHO defined in 2016 the new “Myeloid Neoplasms with Germline Predisposition” category of tumors. High throughput sequencing is frequently performed in tumors either for diagnosis or prognosis, but this approach may identify potential germline variants that have to be confirmed on non-infiltrated tissues.MethodIn this study, we systematically compared NGS data from genetic analysis performed on all sample types (bone marrow, blood, saliva, skin fibroblasts and hair follicles) in 29 patients, and 44 of their relatives (blood and saliva).ResultsWe showed that saliva was usable for relatives, but only for 24% (7/29) of our patients. Most of patients’ saliva were either “non-contributive” (14/29 i.e., 48% because clearly or probably infiltrated) or “inconclusive” (8/29 corresponding to 28%).ConclusionThe recommendations for the use of saliva we present here focus on the importance of collecting saliva during remission when possible. Moreover, we propose hair follicles as an alternative to skin biopsy, that remains the gold standard especially in case of allogenic hematopoietic stem cells transplantation. Technological progresses have revolutionized the diagnosis of predisposition to solid or hematological malignancies, and it is very likely that new techniques will help to manage the familial predisposition in the future

Suivi biologique des patients atteints de leucémie myéloïde chronique traités par Glivec®

LIMOGES-BU Médecine pharmacie (870852108) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF

Etude moléculaire des lymphomes B indolents (exemple des lymphomes de la zone marginale et de la maladie de Waldenström)

Le locus des chaînes lourdes des immunoglobulines est une structure génétique complexe qui subit de nombreux remaniements géniques au cours de la maturation B mais aussi au cours des modèles tumoraux que sont les lymphomes B. Les lymphomes de la zone marginale (MZL) comportent 3 sous-types selon le territoire infiltré : les lymphomes spléniques de la zone marginale (SMZL), les lymphomes ganglionnaires de la zone marginale (NMZL) et les lymphomes des tissus lymphoïdes liés aux muqueuses ou lymphomes de MALT (Mucosa-Associated Lymphoid Tissue). Les MZL partagent parfois des caractéristiques communes avec le lymphome lymphoplasmocytaire/maladie de Waldenström (LPL/WM). Notre travail a consisté en l étude du réarrangement génique de la chaîne lourde de l immunoglobuline des MZL et du LPL/WM. Dans un premier temps, nous avons réalisé une analyse génétique sur des prélèvements médullaires de 11 cas de SMZL et 14 cas de LPL/WM. Le répertoire IGHV, les profils mutationnels et l analyse des HCDR3 ont prouvé qu il s agissait de deux maladies distinctes provenant de deux compartiments cellulaires ayant des expositions à l antigène différentes Dans un deuxième temps, nous avons effectué une comparaison des profils IGHV et une recherche de la mutation MYD88 L265P pour 92 ZML et 31 cas LPL/WM, à partir de matériel tumoral issu du territoire initial d infiltration. Nous avons montré que les SMZL, NMZL et LPL/WM sont des entités distinctes ayant des histoires d exposition antigénique différentes et que la mutation L265P de MYD88 est fortement associée au diagnostic de LPL/WM. Nous avons mis en évidence des critères génétiques IGHV spécifiques pour chacun d entre eux. Enfin, nous proposons des clés diagnostiques non ambiguës pour ces lymphomes. Nous discutons l hypothèse d une stimulation antigénique chronique dans la survenue de ces lymphomes dans un modèle d infection chronique en rapport étroit avec le contexte auto-immun ainsi que l origine cellulaire des SMZL, NMZL et LPL/WM. Les perspectives de ce travail sont d étudier les voies de signalisation impliquées dans la physiopathologie de ces lymphomes.LIMOGES-BU Médecine pharmacie (870852108) / SudocSudocFranceF

Caractérisation moléculaire de le translocation t(3;13)(q22;q13) dans le cadre d'un syndrome myéloprolifératif atypique

LIMOGES-BU Médecine pharmacie (870852108) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Adult Bone Marrow Three-Dimensional Phenotypic Landscape of B-Cell Differentiation

International audienc

Inflamed phenotype of splenic marginal zone B-cell lymphomas with expression of PD-L1 by intratumoral monocytes/macrophages and dendritic cells

International audienc

A reduced panel of eight genes (ATM, SF3B1, NOTCH1, BIRC3, XPO1, MYD88, TNFAIP3, and TP53) as an estimator of the tumor mutational burden in chronic lymphocytic leukemia

International audienceIntroduction: Mutational complexity or tumor mutational burden (TMB) influences the course of chronic lymphocytic leukemia (CLL). However, this information is not routinely used because TMB is usually obtained from whole genome or exome, or from large gene panel high‐throughput sequencing.Methods: Here, we used the C‐Harrel concordance index to determine the minimum panel of genes for which mutations predict treatment‐free survival (TFS) as well as large resequencing panels.Results: An eight gene estimator was defined encompassing ATM, SF3B1, NOTCH1, BIRC3, XPO1, MYD88, TNFAIP3, and TP53. TMB estimated from either a large panel of genes or the eight gene estimator was increased in treated patients or in those with a short TFS (6 months). Strikingly, the eight gene estimator was also highly informative for patients with Binet stage A CLL or with a good prognosis karyotype.Conclusion: These results suggest that the eight gene estimator, that is easily achievable by high‐throughput resequencing, brings robust and valuable information that predicts evolution of untreated patients at diagnosis better than any other parameter

c-Myc dysregulation is a co-transforming event for nuclear factor-κB activated B cells.

International audienceWhile c-Myc dysregulation is constantly associated with highly proliferating B-cell tumors, nuclear factor (NF)-κB addiction is found in indolent lymphomas as well as diffuse large B-cell lymphomas, either with an activated B-cell like phenotype or associated with the Epstein-Barr virus. We raised the question of the effect of c-Myc in B cells with NF-κB activated by three different inducers: Epstein-Barr virus-latency III program, TLR9 and CD40. Induction of c-Myc overexpression increased proliferation of Epstein-Barr virus-latency III immortalized B cells, an effect that was dependent on NF-κB. Results from transcriptomic signatures and functional studies showed that c-Myc overexpression increased Epstein-Barr virus-latency III-driven proliferation depending on NF-κB. In vitro, induction of c-Myc increased proliferation of B cells with TLR9-dependant activation of MyD88, with decreased apoptosis. In the transgenic λc-Myc mouse model with c-Myc overexpression in B cells, in vivo activation of MyD88 by TLR9 induced splenomegaly related to an increased synthesis phase (S-phase) entry of B cells. Transgenic mice with both continuous CD40 signaling in B cells and the λc-Myc transgene developed very aggressive lymphomas with characteristics of activated diffuse large B-cell lymphomas. The main characteristic gene expression profile signatures of these tumors were those of proliferation and energetic metabolism. These results suggest that c-Myc is an NF-κB co-transforming event in aggressive lymphomas with an activated phenotype, activated B-cell like diffuse large B-cell lymphomas. This would explain why NF-κB is associated with both indolent and aggressive lymphomas, and opens new perspectives on the possibility of combinatory therapies targeting both the c-Myc proliferating program and NF-κB activation pathways in diffuse large B-cell lymphomas

Design and Feasibility of a Novel, Rapid, and Simple Fluorescence 26-Plex RT-PCR Assay for Simultaneous Detection of 24 Fusion Transcripts in Adult Acute Myeloid Leukemia.

International audienceIdentification of chromosomal abnormalities is mandatory for classification of acute myeloid leukemia (AML), and the abnormalities have to be determined quickly, to allow patient enrollment in multicenter protocols and/or for selecting therapeutic strategies. Rapid AML molecular diagnosis is often difficult to achieve, however, because it is based on numerous different RT-PCR protocols. We developed a new RT-PCR method, one that does not require a nested step, to simultaneously detect all AML fusion transcripts from six major recurrent translocations found in adults: t(15;17)(q22;q12), inv(16)(p13.1q22) [t(16;16)(p13.1;q22)], t(8;21)(q22;q22), t(6;9)(p23;q34), t(9;22)(q34;q11), and t(10;11)(p13;q14). Specific primers for RT-PCR detection of the 24 fusion transcripts, along with two transcripts for controls, were designed for this 26-plex RT-PCR. Each PCR product had a different size and was separated by capillary electrophoresis. We also designed a multiplex positive control with 24 chimeric RNAs, corresponding to all chimeric RNAs tested. Compared with classical molecular biology protocols and cytogenetic analyses used as reference standards, results of the 26-plex RT-PCR method were concordant in all 204 (100%) cases of adult AML tested. Results were obtained in less than 24 hours. Because of the multiplex positive control, interpretation of the peaks was very easy, without any ambiguity. The tumor cell detection threshold was 1.5%