mutations, notably the recurrent gain-of-function L265P variant, are a distinguishing feature of activated B-cell like (ABC) diffuse large B-cell lymphoma (DLBCL), leading to constitutive NFκB ...pathway activation. The aim of this study was to examine the distinct genomic profiles of
-mutant DLBCL, notably according to the presence of the L265P or other non-L265P MYD88 variants.
A cohort of 361 DLBCL cases (94
mutant and 267
wild-type) was submitted to next-generation sequencing (NGS) focusing on 34 genes to analyze associated mutations and copy number variations, as well as gene expression profiling, and clinical and prognostic analyses.
Importantly, we highlighted different genomic profiles for MYD88 L265P and MYD88 non-L265P-mutant DLBCL, shedding light on their divergent backgrounds. Clustering analysis also segregated subgroups according to associated genetic alterations among patients with the same
mutation. We showed that associated
and MYD88 L265P mutations act synergistically to increase NFκB pathway activation, although the majority of MYD88 L265P-mutant cases harbors downstream NFκB alterations, which can predict BTK inhibitor resistance. Finally, although the MYD88 L265P variant was not an independent prognostic factor in ABC DLBCL, associated
mutations significantly improved the survival of MYD88 L265P-mutant ABC DLBCL in our cohort.
This study highlights the relative heterogeneity of
-mutant DLBCL, adding to the field's knowledge of the theranostic importance of
mutations, but also of associated alterations, emphasizing the usefulness of genomic profiling to best stratify patients for targeted therapy.
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Innate immunity to viral infection involves induction of the type I IFN response; however, dysfunctional regulation of this pathway leads to inappropriate inflammation. Here, we evaluated a ...nonconsanguineous family of mixed European descent, with 4 members affected by systemic inflammatory and autoimmune conditions, including lupus, with variable clinical expression. We identified a germline dominant gain-of-function mutation in TMEM173, which encodes stimulator of type I IFN gene (STING), in the affected individuals. STING is a key signaling molecule in cytosolic DNA-sensing pathways, and STING activation normally requires dimerization, which is induced by 2'3' cyclic GMP-AMP (cGAMP) produced by the cGAMP synthase in response to cytosolic DNA. Structural modeling supported constitutive activation of the mutant STING protein based on stabilized dimerization. In agreement with the model predictions, we found that the STING mutant spontaneously localizes in the Golgi of patient fibroblasts and is constitutively active in the absence of exogenous 2'3'-cGAMP in vitro. Accordingly, we observed elevated serum IFN activity and a type I IFN signature in peripheral blood from affected family members. These findings highlight the key role of STING in activating both the innate and adaptive immune responses and implicate aberrant STING activation in features of human lupus.
The NF-κB family of transcription factors has emerged as a key player in the pathogenesis of multiple myeloma (MM). NF-κB is activated by at least two major signaling pathways. The classical pathway ...results in the activation of mainly RelA containing dimers, whereas the alternative pathway leads to the activation of RelB/p52 and RelB/p50 heterodimers. Activating mutations in regulators of the alternative pathway have been identified in 17% of MM patients. However, the status of RelB activation per se and its role in the regulation of cell survival in MM has not been investigated. Here, we reveal that 40% of newly diagnosed MM patients have a constitutive RelB DNA-binding activity in CD138(+) tumor cells, and we show an association with increased expression of a subset of anti-apoptotic NF-κB target genes, such as cIAP2. Furthermore, we demonstrate that RelB exerts a crucial anti-apoptotic activity in MM cells. Our findings indicate that RelB activation is key for promoting MM cell survival through the upregulation of anti-apoptotic proteins. Altogether, our study provides the framework for the development of new molecules targeting RelB in the treatment of MM.
Purpose Selection bias in clinical trials has consequences for scientific validity and applicability of study results to the general population. There is concern that patients with clinically ...aggressive disease may not have enrolled in recent diffuse large B-cell lymphoma (DLBCL) trials due to the consent process and the inability to delay therapy for eligibility evaluation. We have examined the diagnosis-to-treatment interval (DTI) and its association with clinical factors and outcome in a clinic-based observational cohort of patients with DLBCL from the United States. Validation of results was performed in an independent, clinical trial-based cohort from Europe. Patients and Methods Patients were prospectively enrolled in the University of Iowa and Mayo Clinic Specialized Programs of Research Excellence Molecular Epidemiology Resource (MER; N = 986) or the Lymphoma Study Association (LYSA) LNH-2003 clinical trials program (N = 1,444). All patients received anthracycline-based immunochemotherapy at initial diagnosis. Associations of DTI with clinical factors and outcome were examined. Outcome was assessed using event-free survival at 24 months from diagnosis (EFS24). Results Median (range) DTI was 15 days (0 to 155 days in the MER and 23 days (0 to 215 days) in LYSA. Shorter DTI was strongly associated with adverse clinical factors, including elevated lactate dehydrogenase levels, poor performance status, B symptoms, and higher International Prognostic Index in both cohorts (all P < .001). Longer DTI was associated with improved EFS24 in both the MER (per-week odds ratio, 0.80; 95% CI, 0.74 to .0.87) and LYSA (per-week odds ratio, 0.90; 95% CI, 0.86 to 0.94); association with EFS24 remained significant after adjustment for International Prognostic Index. Conclusion DTI is strongly associated with prognostic clinical factors and outcome in newly diagnosed DLBCL. DTI should be reported in all clinical trials of newly diagnosed DLBCL and future trials should take steps to avoid selection bias due to treatment delay.
Despite the impressive efficacy of chimeric antigen receptor (CAR) T-cell therapy (CART) in B-cell non-Hodgkin lymphomas, durable responses are uncommon. The histopathologic and molecular features ...associated with treatment failure are still largely unknown. Therefore, we have analyzed 19 sequential tumor samples from 9 patients, prior anti-CD19 CART (pre-CART) and at relapse (post-CART), using immunohistochemistry, fluorescence in situ hybridization, array comparative genomic hybridization, next-generation DNA and RNA sequencing, and genome-scale DNA methylation. The initial diagnosis was diffuse large B-cell lymphoma (n=6), double-hit high-grade B-cell lymphoma (n=1), and Burkitt lymphoma (n=2). Histopathologic features were mostly retained at relapse in 7/9 patients, except the frequent loss of 1 or several B-cell markers. The remaining 2 cases (1 diffuse large B-cell lymphoma and 1 Burkitt lymphoma) displayed a dramatic phenotypic shift in post-CART tumors, with the drastic downfall of B-cell markers and emergence of T-cell or histiocytic markers, despite the persistence of identical clonal immunoglobulin gene rearrangements. The post-CART tumor with aberrant T-cell phenotype showed reduced mRNA expression of most B-cell genes with increased methylation of their promoter. Fluorescence in situ hybridization and comparative genomic hybridization showed global stability of chromosomal alterations in all paired samples, including 17p/TP53 deletions. New pathogenic variants acquired in post-CART samples included mutations triggering the PI3K pathway (PIK3R1, PIK3R2, PIK3C2G) or associated with tumor aggressiveness (KRAS, INPP4B, SF3B1, SYNE1, TBL1XR1). These results indicate that CART-resistant B-cell non-Hodgkin lymphomas display genetic remodeling, which may result in profound dysregulation of B-cell differentiation. Acquired mutations in the PI3K and KRAS pathways suggest that some targeted therapies could be useful to overcome CART resistance.
•Reproducibility between expert pathologists to evaluate pT of thymomas is problematic.•Thymomas may grow with their “capsule” adhering to rather than invading into lung or pericardium.•Mediastinal ...pleura is difficult to recognize on microscopy.•Recognizing the outer pericardial layer from the fibrous part is important for pericardial invasion diagnosis.•Highly contrasted elastic stains as well as immunohistochemical markers that highlight mesothelial and tumor cells can aid in the evaluation of lung invasion.
Pathologists are staging thymic epithelial tumors (TET) according to the 8th UICC/AJCC TNM system. Within the French RYTHMIC network, dedicated to TET, agreement on pathologic tumor stage (pT) among the pathology panelists was difficult. The aim of our study was to determine the interobserver reproducibility of pT at an international level, to explore the source of discrepancies and potential interventions to address these.
An international panel of pathologists was recruited through the International Thymic Malignancy Interest Group (ITMIG). The study focused on invasion of mediastinal pleura, pericardium, and lung. From a cohort of cases identified as challenging within the RYTHMIC network, we chose a series of test and validation cases (n = 5 and 10, respectively).
Reproducibility of the pT stage was also challenging at an international level as none of the 15 cases was classified as the same pT stage by all ITMIG pathologists. The agreement rose from slight (κ = 0.13) to moderate (κ = 0.48) between test and validation series. Discussion among the expert pathologists pinpointed two major reasons underlying discrepancies: 1) Thymomas growing with their “capsule” and adhering to the pleurae, pericardium, or lung were often misinterpreted as invading these structures. 2) Recognition of the mediastinal pleura was identified as challenging.
Our study underlines that the evaluation of the pT stage of TET is problematic and needs to be addressed in more detail in an upcoming TNM classification. The publication of histopathologic images of landmarks, including ancillary tests could improve reproducibility for future TNM classifications.
Classification of thymic epithelial tumours (TETs) is known to be challenging; however, the level of discordances at a nationwide level between initial and expert diagnosis and their clinical ...consequences are currently unknown. RYTHMIC is a national network dedicated to the management of TET based on initial histological diagnosis, followed by an additional expert review of all cases. Our aim was to evaluate the discordances between initial and expert diagnoses and whether they would have led to different clinical management.
We conducted a retrospective analysis of the cohort of patients discussed at RYTHMIC tumour board from January 2012 to December 2016. Assessment of disagreement was made for histological typing and for staging. The discordances were classified as major or minor based on whether they would have changed or not the proposed therapeutic strategy, respectively. Follow-up of the patients with major discordances was conducted until December 2018.
Four hundred sixty-seven patients were reviewed, and 183 (39%) discordances were identified either related to histological subtype (132) and/or stage (72). Major discordances were identified in 27 patients (6%). They included 16 patients with TET for whom treatment recommendation based on the central review would have been post-operative radiotherapy, whereas it had not been the case. However, follow-up did not show any progression among the 15 patients with high-grade histology and/or stage resected thymomas. On the other hand, among the remaining 11 patients including 7 with a diagnosis other than TET, the overall management or follow-up would have been completely different with the expert diagnosis.
Our real-life cohort reveals a high level of discordances considering TET diagnosis and supports expert review for optimal clinical management.
•We analysed the impact of expert pathologic review of thymic epithelial tumours (TETs) in a nationwide network.•A cohort of 467 patients with TET was studied in a real-life setting.•We identified an overall discordance rate of 39% considering histotype and/or stage.•Change for post-operative radiotherapy or disease management involved 6% of patients.•Expert pathologic review of TET contributes to a better treatment decision-making.
To evaluate the prognostic value of cell of origin immunohistochemical markers and BCL2, BCL6, and c-MYC translocations in a homogeneous cohort of patients with diffuse large B-cell lymphoma (DLBCL) ...treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP).
Patients with CD20+ DLBCL were enrolled in the randomized LNH98-5 and 01-5B Groupe d'Etude des Lymphomes de l'Adulte trials. Paraffin-embedded tumor samples of 119 patients treated with R-CHOP were analyzed by immunohistochemistry for CD10, BCL6, MUM1/IRF4, LMO2, and forkhead box protein P1 (FOXP1) expression and for BCL2, BCL6, and c-MYC breakpoints by fluorescence in situ hybridization (FISH) on tissue microarray.
LMO2 expression and BCL2 breakpoint were associated with the germinal center (GC) subtype defined by Hans' algorithm, respectively (P < .0001; P = .0002) whereas FOXP1 expression and BCL6 breakpoint were associated with the non-germinal center (non-GC) subtype (P = .008 and P = .0001, respectively). The immunohistochemical markers analyzed independently, GC/non-GC phenotype and BCL2 breakpoint did not predict overall survival (OS). BCL6 breakpoint was significantly associated with an unfavorable impact on OS (P = .04). Interestingly, an immunoFISH index, defined by positivity for at least two of three non-GC markers (FOXP1, MUM1/IRF4, BCL6 breakpoint) was significantly associated with a shorter 5-year OS rate (44%; 95% CI, 28 to 60 v 78%; 95% CI, 59 to 89; P = .01) which was independent (P = .04) of the age-adjusted International Prognostic Index (P = .04) in multivariate analysis.
Our study demonstrates that combining immunohistochemistry with FISH allows construction of an immunoFISH index that significantly predicts survival in elderly DLBCL patients treated with R-CHOP.
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