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Epstein-Barr virus (EBV)-associated diffuse large B-cell lymphoma (DLBCL) of the elderly constitutes a provisional clinicopathological entity in the current World Health Organization (WHO) classification and its genomic features remain sparsely characterized. We investigated a cohort of 26 cases of untreated de novo EBV-positive DLBCL of the elderly by high-resolution array-based comparative genomic profiling and fluorescence in situ hybridization (FISH). Moreover, we screened for activating mutations affecting nuclear factor (NF)-κB pathway signaling and chromatin remodeling (EZH2, CD79B, CARD11 and MYD88) due to their impact of gene expression signatures and postulated upcoming therapeutic targetability. We identified an overlap between genomic aberrations previously described to be exclusive features of plasmablastic lymphoma (PL), post-transplant lymphoproliferative disorder (PTLD) and DLBCL, respectively, indicating a close cytogenetic relationship between these entities. Few mutations affecting CD79B and CARD11 and no MYD88 mutations were detectable, hinting at EBV-mediated activation of NF-κB as an alternative to pathologically enforced B-cell receptor signaling in this rare entity. [ABSTRACT FROM AUTHOR]

Double-hit lymphomas (DHL) with MYC and either BCL2 or BCL6 rearrangements are rare neoplasms with an aggressive clinical presentation and grim prognosis. Moreover, molecular characterization of DHL remains insufficient, and especially the role of TP53 pathway disruption is unknown. We employed a next-generation sequencing approach to investigate the mutational status of TP53 in DHL and correlated genomic data with immunohistochemical reactivity for p53. We identified TP53 mutations in MYC+/BCL2+ lymphomas at a frequency intermediate between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. Remarkably, TP53 mutations were particularly scarce in MYC+/BCL6+ lymphomas. Our findings indicate a significant difference between these two types of DHL at a molecular level with pathogenetic implications, as arguably, TP53 mutations inhibiting p53 mediated promotion of apoptosis pose a synergistic advantage in clonal evolution of cells with malignantly enforced overexpression of BCL2. Immunohistochemical staining appears to be a sensitive surrogate of TP53 mutation status with moderate specificity. [ABSTRACT FROM AUTHOR]

The article presents research on the mutation status of nodal marginal zone lymphoma (NMZL) and the recurrent lesions. Topics discussed include an overview of NMZL, the analysis of the mutation status of transmembrane proteins CD79A , CD79B and MYD88, and the expected pattern of mutations and their genetic variations.

A letter to the editor is presented that the Spinocerebellar ataxia type 4 (SCA4) and the 16q22.1-linked Japanese ataxia are not allelic.

High-grade B-cell lymphoma accompanied with double/triple-hit MYC and BCL2 and/or BCL6 rearrangements (HGBLDH/ TH) poses a cytogenetically-defined provisional entity among aggressive B-cell lymphomas that is traditionally associated with unfavorable prognosis. In order to better understand the mutational and molecular landscape of HGBLDH/ TH we here performed whole-exome sequencing and deep panel next-generation sequencing of 47 clinically annotated cases. Oncogenic drivers, mutational signatures and perturbed pathways were compared with data from follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). We find an accumulation of oncogenic mutations in NOTCH, IL6/JAK/STAT and NFκB signaling pathways and delineate the mutational relationship within the continuum between FL/DLBCL, HGBL-DH/TH and BL. Further, we provide evidence of a molecular divergence between BCL2 and BCL6 rearranged HGBL-DH. Beyond a significant congruency with the C3/EZB DLBCL cluster in BCL2 rearranged cases on an exome-wide level, we observe an enrichment of the SBS6 mutation signature in BCL6 rearranged cases. Differential gene set enrichment and subsequent network propagation analysis according to cytogenetically defined subgroups revealed an impairment of TP53 and MYC pathway signaling in BCL2 rearranged cases, whereas BCL6 rearranged cases lacked this enrichment, but instead showed impairment of E2F targets. Intriguingly, HGBL-TH displayed intermediate mutational features considering all three aspects. This study elucidates a recurrent pattern of mutational events driving FL into MYC-driven BCL2-rearranged HGBL, unveiling the mutational pathogenesis of this provisional entity. Through this refinement of the molecular taxonomy for aggressive, germinal center-derived B-cell lymphomas, this calls into question the current World Health Organization classification system, especially regarding the status of MYC/BCL6- rearranged HGBL.

Background: Angioimmunoblastic T-cell lymphomas (AITLs) are the second most frequent peripheral T-cell lymphomas in humans worldwide and histomorphologically well characterized. MicroRNAs are a group of small non-coding RNAs that can negatively regulate gene expression on a posttranscriptional level. Their dysregulation has been shown to be of importance in numerous tumour entities., Materials and Methods: As a first step towards understanding the possible influence of microRNA-dysregulation in AITL, we analyzed the expression signatures of 760 microRNAs in 30 nodal AITLs in comparison to reactive lymphadenitis with T-zone hyperplasia., Results: We found miR-34a, miR-146a and miR-193b to be up-regulated, as well as miR-140-3p, let-7g, miR-30b and miR-664 to be down-regulated in AITL to a significant level., Conclusion: The microRNA-signatures of AITL reveal some overlap to autoimmune diseases, virus-triggered lymphomas and angiogenic factors that, coupled with future studies, will potentially provide better understanding of this disease., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Aim: To investigate the prognostic role of genomic stability and copy number alterations (CNAs) pancreatic neuroendocrine tumors (PanNETs)., Methods: A high-resolution array-based comparative genomic hybridization approach was utilized in order to investigate and quantify chromosomal aberrations in a panel of 37 primary PanNET and 11 metastatic samples. DNA samples were extracted from formalin-fixed and paraffin-embedded tumor specimen. Genomic findings were correlated with histopathological and immunohistochemical data. Moreover, the dataset was subjected to employing an unsupervised hierarchical clustering analysis approach utilizing Euclidean distance and average linkage and associations between genomically defined tumor groups and recurrent CNAs or clinicopathological features of the study group were assessed., Results: Numerous chromosomal aberrations were recurrently detected in both, primary tumor samples and metastases. Copy number gains were most frequently observed at 06p22.2-p22.1 (27.1%), 17p13.1 (20.8%), 07p21.3-p21.2 (18.8%), 09q34.11 (18.8%). Genomic losses were significantly less frequent and the only recurrent aberration affected 08q24.3 (6.3%). Moreover, we detected a high degree of genomic heterogeneity between primary tumors and metastatic lesions. Unsupervised hierarchical clustering of loci affected by CNAs in more than 3 primary tumor samples revealed two genetically distinct tumor groups as well as two chromosomal clusters of genomic imbalances indicating a small subset of tumors with common molecular features (13.5%). Aberrations affecting 6p22.2-22.1, 8q24.3, 9q34.11 and 17p13.1 (P = 0.011; 0.003; 0.003; 0.001), were significantly associated with a poorer survival prognosis., Conclusion: This study suggests that several frequent CNAs in numerous candidate regions are involved in the pathogenesis and metastatic progression of PanNET.

Background: Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of diffuse large B-cell lymphoma (DLBCL) frequently observed in young patients. High-dose immunochemotherapy constitutes the current therapeutic gold-standard, despite significant toxicity and serious late effects. Several hotspots harboring oncogenic gain-of-function mutations were recently shown to pose vital hallmarks in activated B-cell like (ABC-) (CD79B, CARD11 and MYD88) and germinal center like (GCB-) DLBCL (EZH2), respectively. Several promising targeted-therapy approaches, derived from these findings, are currently under development., Materials and Methods: We thoroughly characterized a cohort of 25 untreated patients with de novo PMBL by immunohistochemical and cytogenetic means and assessed the prevalence of activating mutations affecting EZH2, CD79B and CARD11 utilizing a polymerase chain reaction (PCR)-based capillary sequencing approach. Moreover, the MYD88 p. L265P status was assessed by employing a pyrosequencing approach., Results: PMBLs included in this study did not harbor any of the reported hotspot mutations activating the nuclear factor (NF)-kappa B signaling cascade or the EZH2-mediated epigenetic deregulation of gene expression. Immunohistochemical characterization revealed an ABC phenotype in 44% (n=11) of cases., Conclusion: We report that genetic alterations of these genes are rare events in PMBL unlike other subtypes of DLBCL. Our findings suggest that a substantial subset of PMBL patients may benefit from treatment approaches targeting BCR-mediated activation of NF-kappa B., (Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Pancreatic neuroendocrine neoplasms (pNEN) are rare tumors with a poor prognosis. Although increasing data have accumulated on the molecular pathology of pNEN, very scarce data exist on microRNAs in pNEN and no data are published on microRNAs as potential biomarkers of pNEN in serum. This study aimed to identify microRNA signatures of pNEN in tissue and serum., Materials and Methods: We included tissue samples from 37 patients with pNEN, 9 patients with non-neoplastic pancreatic pathology, seven samples of micro-dissected pancreatic islets and serum samples of 27 patients with pNEN, as well as of 15 healthy volunteers. MicroRNA expression profiles were established using real-time quantitative Polymerase Chain reaction (PCR) for 754 microRNAs., Results: MicroRNA signatures differed between pNEN, pancreatic islets and total pancreas, with virtually no overlap between the groups of de-regulated microRNAs. Expression of miR-642 correlated with Ki67 (MiB1) score and miR-210 correlated with metastatic disease. When comparing microRNA levels in serum from patients with pNEN and healthy volunteers, 13 microRNAs were more abundant in the serum of patients. MiR-193b was also up-regulated in pNEN tissue when compared to pancreatic islets and remained significantly increased in serum even when corrected for multiple testing., Conclusion: Evaluation of microRNAs appears to be promising in the assessment of pNEN. In particular, miR-193b, which is also increased in serum, may be a potential new biomarker of pNEN.

Background: MicroRNAs are regulators of gene expression implicated in vital cellular processes including differentiation, cell growth and apoptosis. Distinct microRNA signatures have been identified for many malignancies including follicular lymphoma (FL). However, no microRNA expression profile characteristic of FL subtypes, e.g. FL with B-cell lymphoma-6 (BCL6) locus rearrangement (FL(BCL2+/BCL6+), FL(BCL2-/BCL6+)) or FL with diffuse growth pattern have been reported., Materials and Methods: MicroRNA signatures from 44 cases of FL were generated employing a quantitative real-time polymerase chain reaction approach. 15 cases of diffuse FL and 15 cases of FL(BCL2+/BCL6+)/FL(BCL2-/BCL6+) were compared against 14 cases of typical FL(BCL2+/BCL6-)., Results: Numerous microRNAs were found to be differentially expressed between FL(BCL2+/BCL6+) and FL(BCL2-/BCL6+), as well as diffuse FL, when compared to typical cases of FL. Up-regulation of several oncogenic microRNAs as well as down-regulation of tumor-suppressor microRNAs was identified. Cluster analysis, however, revealed no microRNA signatures distinct from the reference group for either subtype., Conclusion: These results indicate an involvement of microRNAs in the pathogenesis of FL and its subtypes. Marked de-regulation of oncogenic RNAs and tumor suppressors appears to correspond with a more aggressive phenotype frequently observed in FL(BCL2+/BCL6+), FL(BCL2-/BCL6+) and diffuse FL.

Decalcified formalin-fixed and paraffin-embedded (dFFPE) bone marrow trephines remain the primary source of gDNA in hematopathological diagnostics. Here, we investigated the applicability of next-generation sequencing (NGS) to dFFPE samples. Chronic myelomonocytic leukaemia (CMML) is a haematopoietic stem cell malignancy delineated by genetic heterogeneity. Recently characteristic mutations have been identified for this entity in a distinct group of genes (TET2, CBL, KRAS). We comparatively investigated DNA extracted from fresh mononuclear cells as well as dFFPE samples from four CMML patients employing a commercially available primer set covering the above mentioned and well characterized mutational hotspots in CMML followed by an amplicon based next-generation deep-sequencing (NGS) approach. As we observed high quality run data as well as complete concordance between both sample types in all cases, we further validated the potential of NGS in hematopathology on a larger cohort of CMML patients (n=39), detecting sequence variations in 84.6% of patients. Sequence analysis revealed 92 variants, including five known polymorphisms, ten silent mutations, 36 missense mutations, 14 nonsense mutations, 24 frame shift mutations and three potential splice site mutations. Our findings ultimately demonstrate the applicability of NGS to dFFPE biopsy specimen in CMML and thus allowing the pathologist to evaluate prognostically relevant mutations at a high resolution and further contribute to risk stratification for the individual patient.

Background: The mechanisms promoting malignant transformation from chronic Helicobacter pylori-gastritis to gastric extranodal marginal zone lymphoma (MALT lymphoma) are insufficiently characterized. This follow-up study aimed to validate candidate microRNAs (miRs) in the process of neoplastic transformation., Materials and Methods: MicroRNA expression signatures (n=20) were generated for a total of 60 cases of gastric lesions ranging from Wotherspoon 0-5 employing a quantitative real-time polymerase chain reaction (PCR) approach. Morphological and immunohistochemical characterization of the cohort was supplemented by PCR-based immunoglobulin heavy chain recombination studies., Results: Quantitative expression of miR-150, miR-142.3p, miR-375 and miR-494 was significantly de-regulated in samples from MALT lymphoma compared to those from gastritis., Conclusion: The previously reported up-regulation of miR-150 in marginal zone lymphoma of MALT type was verified in an independent cohort of lymphoma samples employing a modified methodology. This further substantiates the role of miR-150 as a potential oncomiR in MALT lymphoma.

Background: Double-hit lymphomas (DHL) with chromosomal rearrangements affecting the avian myelocytomatosis viral oncogene homolog (cMYC) and either the B-cell lymphoma-2 (BCL2) or -6 (BCL6) locus are uncommon neoplasms with an aggressive clinical course and dismal prognosis. Most cases exhibit a phenotype intermediate between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. Recently mutations affecting the inhibitor of DNA binding 3 (ID3), a helix-loop-helix protein regulating cell cycle progression and B-cell differentiation, were identified as being molecular hallmarks in Burkitt lymphoma, with only rare mutations being found in other lymphomas with translocations affecting cMYC., Materials and Methods: In the present study, we evaluated the mutational status of ID3 in 37 cases of DHL and 16 cases of sporadic Burkitt lymphoma in order to identify a possible association of this new found hallmark with the rare and insufficiently-defined entity of DHL, seeking to broaden the understanding of these lymphomas at a molecular level., Results: We identified ID3 mutations in lymphomas with chromosomal aberrations at cMYC and either BCL2 or BCL6 at a frequency intermediate between that of DLBCL and Burkitt lymphoma, hinting at a common pathway in lymphomagenesis for a subset of patients with DHL., Conclusion: The results of this study assist in the molecular characterization of these highly aggressive lymphomas, potentially giving rise to novel therapeutic approaches.