Successive occurrence of 2 Genetically distinct Burkitt lymphomas: pathophysiological significance and clinical consequences

Nous rapportons le cas exceptionnel d’un patient âgé de 25 ans qui a développé, en moins de 2 ans, 2 lymphomes de Burkitt (LB). La cytogénétique et les techniques de biologie moléculaire ont montré que les 2 LB étaient issus de 2 clones distincts

Molecular characteristics of multifocal brain histiocytic sarcoma

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Cyclin D1-positive Mediastinal Large B-Cell Lymphoma With Copy Number Gains of CCND1 Gene: A Study of 3 Cases With Nonmediastinal Disease.

Primary mediastinal large B-cell lymphoma (PMBL) is a mature large B-cell lymphoma of putative thymic B-cell origin involving the mediastinum with younger age distribution and better prognosis than diffuse large B-cell lymphoma (DLBCL), not otherwise specified. Recently, based on gene expression profile analysis and morphologic findings, cases of PMBL without mediastinal involvement have been reported. In this study, we analyzed 3 cases of nodal DLBCL with morphologic features of PMBL presenting in submandibular or supraclavicular lymph nodes, in middle-aged to elderly patients, 2 of them without clinical or radiologic evidence of mediastinal involvement. The 3 patients presented with stage I/II disease and had excellent response to R-CHOP/R-EPOCH therapy. The 3 cases showed MAL expression and were positive for CD23 and/or CD30. All 3 cases expressed cyclin D1 with copy number gains of CCND1 gene but without rearrangement. There was no rearrangement of CIITA or PDL1/PDL2. Reverse transcriptase-multiplex ligation-dependent probe amplification, a mRNA-based gene expression profile analysis revealed high probability of PMBL (87.6%, 98.7%, and 99%) in these 3 cases. Targeted next-generation sequencing analysis showed SOCS1 mutations in the 3 cases, and TNFAIP3 and XPO1 mutations in one, further supporting the diagnosis of PMBL. In conclusion, we report 3 cases of nodal PMBL, 2 of them without mediastinal mass, and expression of cyclin D1 due to copy number gains of CCND1 gene, a diagnostic pitfall with mantle cell lymphoma and DLBCL, not otherwise specified

TARGETED GENOTYPING OF CIRCULATING TUMOR DNA FOR CLASSICAL HODGKIN LYMPHOMA MONITORING: A PROSPECTIVE STUDY

International audienceAbout Related Information ePDFPDF Request permission Export citation Add to favorites Track citationShare a linkShare on Email Facebook Twitter LinkedIn RedditIntroduction: The relevance of circulating tumor DNA (ctDNA) analysis as a liquid biopsy and minimal residual disease tool in the management of classical Hodgkin Lymphoma (cHL) patients was demonstrated in retrospective settings and remains to be confirmed.Methods: We developed a targeted Next‐Generation sequencing (NGS) panel for fast analysis (AmpliSeq® technology) of nine commonly mutated genes in biopsy and ctDNA of cHL patients. We then conducted a prospective trial to assess ctDNA follow up at diagnosis and after 2 cycles of chemotherapy (C2). A dedicated bioinformatics pipeline to optimize detections of variants with low rates and minimize artefactual misinterpretations was built. Sixty cHL patients treated by first line conventional chemotherapy (BEACOPPescalated [21.3%], ABVD/ABVD‐like [73.5%] and other regimens [5.2%, for elderly patients] were included in this non‐interventional study (NCT02815137).Results: Median age of the patients was 33.5 years (range 20‐86) with a predominance of male patients, scleronodular subtype and ECOG 0‐1 (53.3%, 70% and 88.3%, respectively). Variants were identified in 33 (55%) patients, precisely in 16/30 (53.3%) and 30/60 (50%) of available biopsy and ctDNA samples respectively. Concordance between genetic profiles of biopsy and ctDNA was accurate for 22/30 patients (73.3%). Mutations of NFKBIE, TNFAIP3, STAT6, PTPN1, B2M, XPO1, ITPKB, GNA13 and SOCS1were found in 11.7% (mean number of variants by sample [range]: 1 [0‐1]), 25% (1.1 [0‐2]), 21.7% (1.4 [0‐2]), 1.7% (1 [0‐1]), 25% (1.3 [0‐3]), 6.7% (1 [0‐1]), 15% (1.4 [0‐3]), 5% (1.3 [0‐2]) and 31.7% (1.8 [0‐7]) of all patients, respectively. Unsupervised hierarchical clustering was performed among the 9 genes to represent the association of alterations (See Figure 1).Higher level of [ctDNA] at diagnosis was associated with adverse characteristics: age ≥45 years, presence of anemia (hemoglobin <10.5g/dl), albuminemia <40g/l, sedimentation rate ≥50mm, stage III‐IV, lymphocytes count <0.6 G/L, presence of B symptoms, International prognostic Index ≥3, elevated LDH. The ITPKB and B2M mutated patients displayed more disseminated disease (≥ 4 median nodal areas versus [vs] 3 for non‐mutated patients, p = 0.005) and XPO1 mutations were associated with female sex (p = 0.042). Median VAF were higher in ctDNA than in biopsy (3.23% vs 2.15%, p = 0.023) and there was a moderate correlation between higher metabolic tumor volume (MTV) and higher [ctDNA] (r = 0.36, p = 0.005).Regarding early therapeutic response, 45 patients (83%, NA = 6) had a negative positron emission tomography (PET) after C2 (Deauville Score 1‐3). Mean of DeltaSUVmax after C2 was ‐78.8%. We analyzed ctDNA after C2 for 45 patients (70%). A rapid clearance of ctDNA in all cases was observed after C2.Conclusions: Variants detection in ctDNA is suitable to depict the genetic features of cHL at diagnosis and may help to assess early treatment response, in complement to PET. [ctDNA] level and genotype are correlated with clinical characteristics and presentation.Keywords: classical Hodgkin lymphoma (cHL); minimal residual disease (MRD); molecular genetics.imag

THE LANDSCAPE OF SOMATIC MUTATIONS OF PRIMARY CUTANEOUS DIFFUSE LARGE B-CELL LYMPHOMA, LEG-TYPE

International audienceIntroduction: Primary cutaneous diffuse large B‐cell lymphoma leg‐type (PCLBCL‐LT) is recognized by the World Health Organization (WHO) classification as a rare and aggressive disease accounting for 5 to 10% of primary cutaneous lymphoma. It displays original clinical features occurring mostly in the elderly and preferentially involving the legs but date the genetic specificities of this entities, as compared to other B‐cell aggressive lymphoma is unknown.Methods: To determine whether the mutational profile of primary cutaneous diffuse large B‐cell lymphoma leg‐type (PCLBCL‐LT) is unique by comparison with other diffuse large B‐cell lymphoma (DLBCL) subtypes, we analyzed a total cohort of 28 PCLBCL‐LT cases by next generation sequencing with a Lymphopanel designed for DLBCL. We also analyzed 12 pairs of tumor and control DNA samples by whole exome sequencing which led us to perform resequencing of three selected genes not included in the Lymphopanel: TBL1XR1, KLHL6 and IKZF3. To pinpoint specificities, comparison with a cohort of DLBCL and Primary central nervous System lymphoma (PCNSL) analyzed by the same targeted panel was performed.Results: Our study clearly identifies an original mutational landscape of PCLBCL‐LT with a very restricted set of highly recurrent mutations (>40%) involving MYD88 (p.L265P variant), PIM1 and CD79B. Other genes involved in B‐cell signaling, NFKB activation or DNA modeling were found altered notably TBL1XR1 (33%), MYC (26%) CREBBP (26%) and IRF4 (21%) or HIST1H1E(41%). MYD88L265P variant was associated with copy number variations or copy neutral loss of heterozygosity in 60% of cases. The most frequent genetic losses involved CDKN2A/2B, TNFAIP3/A20, PRDM1, TCF3 and CIITA. The high recurrence of specific gene mutations such as MYD88 and the absence of mutations of KMT2D or FOXO1 are distinct features from nodal DLBCLs of either GC or ABC subtypes. Interestingly PCLBCL‐LT exhibits a mutational pattern that is closer to PCNSL than to ABC‐type nodal DLBCL but also has distinctive features, such as a very high mutational rate for PIM1, a higher rate of CD79B mutations and other original mutations such as CREBBP, MYC and IRF4 mutations (figure 1).Conclusion: This study describes for the first time the genomic landscape of a series of untreated PCLBCL‐LT. Our results obtained by WES and targeted sequencing underscore several similarities with ABC‐DBCL and more specifically with PCNSL subtypes. On the other hand, we pinpoint specificities that may sustain distinctive clinical features and guide therapeutic strategies according to an individual genetic analysis