Histopathological growth patterns in patients with advanced nodular lymphocyte-predominant Hodgkin lymphoma treated within the randomized HD18 study: a report from the German Hodgkin Study Group.

We retrospectively investigated histopathological growth patterns in individuals with advanced nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) treated within the randomized HD18 study. In all, 35/60 patients (58%) presented with atypical growth patterns. Patients with atypical growth patterns more often had stage IV disease (P = 0·0354) and splenic involvement (P = 0·0048) than patients with typical growth patterns; a positive positron emission tomography after two cycles of chemotherapy (PET-2) tended to be more common (P = 0·1078). Five-year progression-free survival [hazard ratio (HR) = 0·86; 95% confidence interval (CI) = 0·49-1·47] and overall survival (HR = 0·85; 95% CI = 0·49-1·51) did not differ between the groups after study treatment with PET-2-guided escalated BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone). Thus, advanced NLPHL is often associated with atypical growth patterns but their prognostic impact is compensated by PET-2-guided escalated BEACOPP.

Localized- and advanced-stage follicular lymphomas differ in their gene expression profiles.

The genetic background of follicular lymphomas (FLs) diagnosed in advanced clinical stages III/IV, and which are frequently characterized by t(14;18), has been substantially unraveled. Molecular features, as exemplified in the clinicogenetic risk model m7FLIPI, are important tools in risk stratification. In contrast, little information is available concerning localized-stage FL (clinical stages I/II), which accounts for ∼20% of newly diagnosed FL in which the detection rate of t(14;18) is only ∼50%. To investigate the genetic background of localized-stage FL, patient cohorts with advanced-stage FL or localized-stage FL, uniformly treated within phase 3 trials of the German Low-Grade Lymphoma Study Group, were comparatively analyzed. Targeted gene expression (GE) profiling of 184 genes using nCounter technology was performed in 110 localized-stage and 556 advanced-stage FL patients. By penalized Cox regression, a prognostic GE signature could not be identified in patients with advanced-stage FL, consistent with results from global tests and univariate regression. In contrast, it was possible to define robust GE signatures discriminating localized-stage and advanced-stage FL (area under the curve, 0.98) by penalized logistic regression. Of note, 3% of samples harboring an "advanced-stage signature" in the localized-stage cohort exhibited inferior failure-free survival (hazard ratio [HR], 7.1; P = .0003). Likewise, in the advanced-stage cohort, 7% of samples with a "localized-stage signature" had prolonged failure-free survival (HR, 2.3; P = .017) and overall survival (HR, 3.4; P = .072). These data support the concept of a biological difference between localized-stage and advanced-stage FL that might contribute to the superior outcome of localized FL.

Mutational landscape of high-grade B-cell lymphoma with MYC-, BCL2 and/or BCL6 rearrangements characterized by whole-exome sequencing.

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.

Exhaustion of tumour-infiltrating T-cell receptor repertoire diversity is an age-dependent indicator of immunological fitness independently predictive of clinical outcome in Burkitt lymphoma.

Burkitt lymphoma (BL) is an aggressive B-cell-malignancy derived from germinal-centre B-cells. Curative therapy traditionally requires intensive immunochemotherapy. Recently, immuno-oncological approaches, modulating the T-cell tumour response, were approved for the treatment of a variety of malignancies. The architecture of the tumour-infiltrating T-cell receptor (TCR) repertoire in BL remains insufficiently characterized. We therefore performed a large-scale, next-generation sequencing study of the complimentary-determining region (CDR)-3 region of the TCRß chain repertoire in a large cohort of all epidemiological subtypes of BL (n = 82) and diffuse large B-cell lymphoma (DLBCL; n = 34). Molecular data were subsequently assessed for correlation with clinical outcome. Our investigations revealed an age-dependent immunoprofile in BL as in DLBCL. Moreover, we found several public clonotypes in numerous patients suggestive of shared tumour neoantigen selection exclusive to BL and distinct from DLBCL regardless of Epstein-Barr virus and/or human immunodeficiency virus status. Compared with baseline, longitudinal analysis unveiled significant repertoire restrictions upon relapse (P = 0·0437) while productive TCR repertoire clonality proved to be a useful indicator of both overall and progression-free-survival [OS: P = 0·0001; hazard ratio (HR): 6·220; confidence interval (CI): 2·263-11·78; PFS: P = 0·0025; HR: 3·086; CI: 1·555-7·030]. Multivariate analysis confirmed its independence from established prognosticators, including age at diagnosis and comorbidities. Our findings establish the clinical relevance of the architecture and clonality of the TCR repertoire and its age-determined dynamics in BL.

Evolutionary clonal trajectories in nodular lymphocyte-predominant Hodgkin lymphoma with high risk of transformation.

The B-cell architecture of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is complex since it is composed of malignant lymphocyte-predominant cells along with a rich B-cell bystander environment. To gain insight into molecular determinants of disease transformation, we studied B-cell evolutionary trajectories in lymphoma tissue from diagnosis to relapse or transformation to non- Hodgkin lymphoma by next-generation sequencing of immunoglobulin heavy chains. Patients with NLPHL that later transformed were older and showed IgD negativity, absence of the characteristic IGHV3/IGHD3/IGHJ6 lymphocyte-predominant rearrangement and high repertoire clonality. We constructed phylogenetic trees within the compartment of the malignant clone to investigate clonal evolution. In all relapsing cases, the lymphocyte-predominant rearrangement was identical at diagnosis and relapse. NLPHL cases with transformation showed more complex trajectories with strong intraclonal diversification. The dominant founder clone in transformations showed clonal evolution if derived from the same cell of origin, or arose from a different cell of origin. Together, our data point to a significant role of antigenic drive in the transformation of NLHPL and identify high B-cell repertoire clonality with dominant intraclonal lymphocyte-predominant cell diversification as a hallmark of transformation. Sequencing of initial paraffin-embedded tissue may therefore be applied diagnostically to identify NLPHL cases with high risk of transformation.

Impact of treatment variability and clinicopathological characteristics on survival in patients with Epstein-Barr-Virus positive diffuse large B cell lymphoma.

Patients with EBV-positive diffuse large B cell lymphoma not otherwise specified (EBV+ DLBCL (NOS)) recurrently present with advanced age and reduced performance status. They are therefore insufficiently represented in clinical trials and treatment is likely to differ. Here we assess clinicopathological characteristics, therapeutic variability and clinical outcome in the largest consecutively diagnosed EBV+ DLBCL (NOS) cohort published to date (n = 80; median age 70 years; range 19-90). Centralized and systematic haematopathological panel review was performed. By immunohistochemistry 60/80 patients were CD30-positive. Further, we identified nine EBV+ DLBCL (NOS) patients with associated or composite peripheral T cell lymphoma at diagnosis or relapse (preceded by clonal T cell populations within the initial DLBCL biopsy in 4/5 cases). Most patients (80%) were treated with R-CHOP-type therapy and 16 patients received none or less intensiveprotocols. Upon univariate analysis both R-CHOP-type therapy (OS: P < 0.0001; PFS: P = 0.0617) and negativity for CD30 (OS: P = 0.0002; PFS: P = 0.0002) showed a protective 66 effect, maintained upon multivariate analysis. In a propensity-score matched analysis with a cohort of non-EBV+ DLBCL (NOS) patients, balanced for all revised-international prognostic index factors, we found an EBV-association to hold no significant impact on progression-free and overall survival whilst exhibiting a trend favouring EBV-negativity (OS: P = 0.116; PFS: P = 0.269). Our findings provide insight into the clinical course of EBV+ DLBCL (NOS), highlight the ramifications of CD30-expression and underline the superior therapeutic efficacy of R-CHOP immunochemotherapy. Alternative therapies, incorporating tumour biology (e.g. CD30 directed therapies) need to be explored in EBV+ DLBCL (NOS) patients. Moreover our data advert to the close relationship between EBV+ DLBCL (NOS) and peripheral T cell lymphomas.

The impact of SOCS1 mutations in diffuse large B-cell lymphoma.

Mutations in SOCS1 are frequent in primary mediastinal B-cell lymphoma and classical Hodgkin lymphoma. In the latter, SOCS1 mutations affect the length of the encoded protein (major mutations) and are associated with shorter patient survival. Two independent studies examined the prognostic impact of SOCS1 mutations in diffuse large B-cell lymphoma (DLBCL) and showed differing results. This may be due to the small number of included patients, the heterogeneity of patients' demographics and the distinct treatment schemes in these studies. To overcome the size limitations of these previous studies, we assessed SOCS1 mutations in the RICOVER-60 cohort. The cohort uniformly consists of elderly patients (aged 61-80 years) treated with the CHOP-14 scheme (cyclophosphamide, hydroxydaunorubicin, vincristine, prednisolone at 14-day intervals) with or without an additional rituximab treatment. Patient outcomes were analysed with regard to overall SOCS1 mutation frequency, major and minor mutations and a novel impact-based classifier - against the treatment modalities. Patients harbouring putative pathogenic SOCS1 mutations showed significant reduced overall survival within the CHOP plus rituximab group. Hence, putative pathogenic SOCS1 mutations seem to efface the beneficial effect of the therapeutic CD20 antibody. Comparing published data of whole exome and transcriptome sequencing of a large DLBCL cohort confirmed that predicted deleterious SOCS1 mutations forecast pre-eminent survival in early onset DLBCL.

The time to relapse correlates with the histopathological growth pattern in nodular lymphocyte predominant Hodgkin lymphoma.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) can present with different histopathological growth patterns. The impact of these histopathological growth patterns on relapse characteristics is unknown. We therefore analyzed paired biopsies obtained at initial diagnosis and relapse from 33 NLPHL patients who had received first-line treatment within German Hodgkin Study Group (GHSG) trial protocols, and from a second cohort of 41 relapsed NLPHL patients who had been treated outside GHSG studies. Among the 33 GHSG patients, 21 patients presented with a typical growth pattern at initial diagnosis, whereas 12 patients had a variant histology. The histopathological growth patterns at initial diagnosis and at relapse were consistent in 67% of cases. A variant histology at initial diagnosis was associated with a shorter median time to lymphoma recurrence (2.8 vs 5.2 years; P = .0219). A similar tendency towards a shorter median time to lymphoma recurrence was observed for patients presenting with a variant histology at relapse, irrespective of the growth pattern at initial diagnosis. Results obtained from the 41 NLPHL patients who had been treated outside GHSG studies were comparable (median time to lymphoma recurrence for variant histology vs typical growth pattern at initial diagnosis: 1.5 vs 7.0 years). In conclusion, the histopathological growth pattern remains consistent at relapse in the majority of NLPHL cases, and has major impact on the time of relapse.

Modified BEAM with triple autologous stem cell transplantation for patients with relapsed aggressive non-Hodgkin lymphoma.

Treatment of relapse and primary progression in aggressive lymphoma remains unsatisfactory; outcome is still poor. Better treatment strategies are much needed for this patient population. The R1 study is a prospective multi-center phase I/II study evaluating a dose finding approach with a triple transplant regimen in four BEAM dose levels in patients with relapsed aggressive non-Hodgkin lymphoma. The aim of the study was to determine feasibility, toxicity, and remission rate. In a total of 39 patients (pts.) enrolled in the study, 24 pts. were evaluated in the following analysis. Twenty pts. had aggressive B cell lymphoma, and two pts. had T cell lymphoma. All evaluated patients responded to DexaBEAM with a sufficient stem cell harvest. The phase I/II study was started with BEAM dose level II. Four patients were treated at dose level II, and 20 pts. were treated at dose level III. Due to the early termination of the study, dose levels I and IV were never administered. Sixteen pts. completed therapy according to protocol, and eight pts. (33.3 %) stopped treatment early. Infections (27 %) and stomatitis (13 %) were the most frequent grade III/IV non-hematologic toxicities. Thirteen percent of patients presented with severe grade III/IV lung toxicity during modified BEAM (m-BEAM). Fourteen pts. achieved a complete response (CR), one pt. achieved no change (NC), six pts. had progressive disease (PD), and two pts. died; for one pt., outcome is not known. One-year and 3-year event-free survival (EFS) was 38 and 33 %, respectively. Overall survival (OS) after 1 and 3 years was 50 and 38 %. In conclusion, dose escalation of standard BEAM is not feasible due to toxicity.

XIAP variants in male Crohn's disease.

OBJECTIVE: The genetic basis of inflammatory bowel disease (IBD) is incompletely understood. The aim of this study was to identify rare genetic variants involved in the pathogenesis of IBD. DESIGN: Exome sequencing and immunological profiling were performed in a patient with early onset Crohn's disease (CD). The coding region of the gene encoding X-linked inhibitor of apoptosis protein (XIAP) was sequenced in samples of 275 paediatric IBD and 1047 adult-onset CD patients. XIAP genotyping was performed in samples of 2680 IBD patients and 2864 healthy controls. Functional effects of the variants identified were investigated in primary cells and cultured cell lines. RESULTS: Our results demonstrate the frequent occurrence of private variants in XIAP in about four percent of male patients with paediatric-onset CD. While XIAP mutations are known to be associated with the primary immunodeficiency (PID) X-linked lymphoproliferative disease type 2 (XLP2), CD patients described here exhibited intestinal inflammation in the absence of XLP2 and harboured a spectrum of mutations partially distinct from that observed in XLP2. The majority of XIAP variants identified was associated with a selective defect in NOD1/2 signalling, impaired NOD1/2-mediated activation of NF-κB, and altered NF-κB-dependent cytokine production. CONCLUSIONS: This study reveals the unanticipated, frequent occurrence of XIAP variants in male paediatric-onset CD. The link between XIAP and NOD1/2, and the association of XIAP variants with XLP2, support the concept of PID in a subset of IBD patients. Moreover, these studies provide a rationale for the implementation of XIAP sequencing in clinical diagnostics in male patients with severe CD.

Integration of gene mutations in risk prognostication for patients receiving first-line immunochemotherapy for follicular lymphoma: a retrospective analysis of a prospective clinical trial and validation in a population-based registry.

BACKGROUND: Follicular lymphoma is a clinically and genetically heterogeneous disease, but the prognostic value of somatic mutations has not been systematically assessed. We aimed to improve risk stratification of patients receiving first-line immunochemotherapy by integrating gene mutations into a prognostic model. METHODS: We did DNA deep sequencing to retrospectively analyse the mutation status of 74 genes in 151 follicular lymphoma biopsy specimens that were obtained from patients within 1 year before beginning immunochemotherapy consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). These patients were recruited between May 4, 2000, and Oct 20, 2010, as part of a phase 3 trial (GLSG2000). Eligible patients had symptomatic, advanced stage follicular lymphoma and were previously untreated. The primary endpoints were failure-free survival (defined as less than a partial remission at the end of induction, relapse, progression, or death) and overall survival calculated from date of treatment initiation. Median follow-up was 7·7 years (IQR 5·5-9·3). Mutations and clinical factors were incorporated into a risk model for failure-free survival using multivariable L1-penalised Cox regression. We validated the risk model in an independent population-based cohort of 107 patients with symptomatic follicular lymphoma considered ineligible for curative irradiation. Pretreatment biopsies were taken between Feb 24, 2004, and Nov 24, 2009, within 1 year before beginning first-line immunochemotherapy consisting of rituximab, cyclophosphamide, vincristine, and prednisone (R-CVP). Median follow-up was 6·7 years (IQR 5·7-7·6). FINDINGS: We established a clinicogenetic risk model (termed m7-FLIPI) that included the mutation status of seven genes (EZH2, ARID1A, MEF2B, EP300, FOXO1, CREBBP, and CARD11), the Follicular Lymphoma International Prognostic Index (FLIPI), and Eastern Cooperative Oncology Group (ECOG) performance status. In the training cohort, m7-FLIPI defined a high-risk group (28%, 43/151) with 5-year failure-free survival of 38·29% (95% CI 25·31-57·95) versus 77·21% (95% CI 69·21-86·14) for the low-risk group (hazard ratio [HR] 4·14, 95% CI 2·47-6·93; p<0·0001; bootstrap-corrected HR 2·02), and outperformed a prognostic model of only gene mutations (HR 3·76, 95% CI 2·10-6·74; p<0·0001; bootstrap-corrected HR 1·57). The positive predictive value and negative predictive value for 5-year failure-free survival were 64% and 78%, respectively, with a C-index of 0·80 (95% CI 0·71-0·89). In the validation cohort, m7-FLIPI again defined a high-risk group (22%, 24/107) with 5-year failure-free survival of 25·00% (95% CI 12·50-49·99) versus 68·24% (58·84-79·15) in the low-risk group (HR 3·58, 95% CI 2·00-6·42; p<0.0001). The positive predictive value for 5-year failure-free survival was 72% and 68% for negative predictive value, with a C-index of 0·79 (95% CI 0·69-0·89). In the validation cohort, risk stratification by m7-FLIPI outperformed FLIPI alone (HR 2·18, 95% CI 1·21-3·92), and FLIPI combined with ECOG performance status (HR 2·03, 95% CI 1·12-3·67). INTERPRETATION: Integration of the mutational status of seven genes with clinical risk factors improves prognostication for patients with follicular lymphoma receiving first-line immunochemotherapy and is a promising approach to identify the subset at highest risk of treatment failure. FUNDING: Deutsche Krebshilfe, Terry Fox Research Institute.

The prognostic impact of variant histology in nodular lymphocyte-predominant Hodgkin lymphoma: a report from the German Hodgkin Study Group (GHSG).

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) accounts for approximately 5% of all Hodgkin lymphoma cases. The aim of this study was to evaluate the prognostic implication of histopathologic NLPHL variants. Biopsies of 423 NLPHL patients treated within 9 prospective clinical trials performed by the German Hodgkin Study Group were classified as tumor cell-rich cases (n = 10), typical NLPHL (n = 308), or histopathologic variants (n = 105). Histopathologic variants were characterized by the presence of lymphoma cells outside the B-cell nodules or B-cell depletion of the microenvironment. Compared with typical NLPHL, histopathologic variants were associated with advanced disease (29.5% vs 14.6%, P = .0012) and a higher relapse rate (18.1% vs 6.5% at 5 years, P = .0009). Variant histology represented an independent prognostic factor (odds ratio = 2.955) in a multivariate model of progression/relapse. A prognostic score, including the risk factors variant histopathologic growth pattern, low serum albumin, and male gender, was derived from this model and allowed the definition of 3 distinct risk groups. NLPHL patients presenting with histopathologic variants have a poorer outcome compared with those showing typical histology. The newly developed prognostic score combining histologic and clinical features allows allocating NLPHL patients to defined risk groups.

MYC status in concert with BCL2 and BCL6 expression predicts outcome in diffuse large B-cell lymphoma.

MYC rearrangements occur in 5% to 10% of diffuse large B-cell lymphomas (DLBCL) and confer an increased risk to cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone (CHOP) and rituximab (R)-CHOP treated patients. We investigated the prognostic relevance of MYC-, BCL2- and BCL6-rearrangements and protein expression in a prospective randomized trial. Paraffin-embedded tumor samples from 442 de novo DLBCL treated within the RICOVER study of the German High-Grade Non-Hodgkin Lymphoma Study Group (DSHNHL) were investigated using immunohistochemistry and fluorescence in situ hybridization (FISH) to detect protein expression and breaks of MYC, BCL2, and BCL6. Rearrangements of MYC, BCL2, and BCL6 were detected in 8.8%, 13.5%, and 28.7%, respectively. Protein overexpression of MYC (>40%) was encountered in 31.8% of tumors; 79.6% and 82.8% of tumors expressed BCL2 and BCL6, respectively. MYC translocations, MYChigh, BCL2high, and BCL6low protein expressions were associated with inferior survival. In multivariate Cox regression modeling, protein expression patterns of MYC, BCL2 and BCL6, and MYC rearrangements were predictive of outcome and provided prognostic information independent of the International Prognostic Index (IPI) for overall survival and event-free survival. A combined immunohistochemical or FISH/immunohistochemical score predicts outcome in DLBCL patients independent of the IPI and identifies a subset of 15% of patients with dismal prognosis in the high-risk IPI group following treatment with R-CHOP. Registered at http://www.cancer.gov/clinicaltrials: RICOVER trial of the DSHNHL is NCT 00052936.

MicroRNA profiling of low-grade and transformed nodal marginal zone lymphoma reveals a similar signature pattern distinct from diffuse large B cell lymphoma.

BACKGROUND/AIMS: As critical post-transcriptional regulators of gene expression, microRNAs are involved in several cellular processes of vital impact including cell growth and apoptosis. Many hematologic malignancies exhibit distinct microRNA signatures. MicroRNA implication in the pathogenesis of nodal marginal zone lymphoma (NMZL), however, remains widely elusive. METHODS: Comprehensive morphologic, immunophenotypic and cytogenetic studies were carried out on a cohort of NMZL (n = 30) incorporating indolent as well as transformed MZL. In addition, microRNA signatures were generated, employing a quantitative real-time polymerase chain reaction approach. These were then compared to signatures from cases of diffuse large B cell lymphoma (DLBCL) alongside reactive lymph node controls. RESULTS: While microRNA signatures of low-grade and transformed NMZL did not differ significantly, several microRNAs were differentially expressed between transformed NMZL and DLBCL, hinting at molecularly distinct mechanisms of lymphomagenesis and indicating the biological disparity of transformed NMZL from DLBCL. CONCLUSION: In the light of the unresolved issue regarding the classification of marginal zone-derived transformed B-cell neoplasms, microRNAs may be a valuable aid in discriminating NMZL from DLBCL.

Histopathological features and their prognostic impact in nodular lymphocyte-predominant Hodgkin lymphoma--a matched pair analysis from the German Hodgkin Study Group (GHSG).

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma entity. We performed a matched-pair analysis to evaluate the prognostic impact of several histopathological features in this distinct Hodgkin lymphoma subtype. Lymph node samples of NLPHL patients were tested for CD15, IgD, phosphorylated STAT6, ICOS and Epstein-Barr virus status of the malignant lymphocyte-predominant cells as well as epithelioid cell clusters and activated T cells in the microenvironment. None of these features was associated with a particular clinical outcome. However, patients presenting with epithelioid cell clusters showed a non-significant trend towards a lower relapse rate, justifying further evaluation of this marker.

Intravascular natural killer cell lymphoma mimicking mycosis fungoides: a case report and review of the literature.

Intravascular lymphoma is a rare entity. Most cases constitute a variant of extranodal diffuse large B-cell lymphoma, and only 10% of the published cases are of T-cell or histiocytic origin. Even fewer cases of intravascular natural killer (NK) cell lymphoma have been reported. To date, only the intravascular lymphoma of B-cell linage is recognized as a distinct entity by the WHO Classification. Here, we report the clinical, morphological, immunohistochemical, and molecular findings of a 72-year-old male patient with intravascular NK-cell lymphoma of the skin who initially presented with red skin efflorescences suspicious of mycosis fungoides. A skin biopsy revealed large cell infiltrates of NK/T-cell phenotype (CD3ε, CD4, CD8, CD56, and TIA-1), which were localized strictly intravascularly and which were positive for Epstein-Barr virus nucleic acid EBER (Epstein-Barr virus-encoded small RNA). Molecular studies revealed a germline configuration for the T-cell receptor consistent with the possibility of an NK-cell origin. At the beginning, the disease appeared to be limited to the skin with no sign of bone marrow involvement or leukemic dissemination. Chemotherapy was initiated; however, the patient subsequently developed meningiosis lymphomatosa with recurrent epileptic episodes and bone marrow infiltration with pancytopenia 7 months after primary admission. Finally, the patient passed away in a septic shock.

Genome-wide DNA methylation-analysis of blastic plasmacytoid dendritic cell neoplasm identifies distinct molecular features.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) constitutes a rare and aggressive malignancy originating from plasmacytoid dendritic cells (pDCs) with a primarily cutaneous tropism followed by dissemination to the bone marrow and other organs. We conducted a genome-wide analysis of the tumor methylome in an extended cohort of 45 BPDCN patients supplemented by WES and RNA-seq as well as ATAC-seq on selected cases. We determined the BPDCN DNA methylation profile and observed a dramatic loss of DNA methylation during malignant transformation from early and mature DCs towards BPDCN. DNA methylation profiles further differentiate between BPDCN, AML, CMML, and T-ALL exhibiting the most striking global demethylation, mitotic stress, and merely localized DNA hypermethylation in BPDCN resulting in pronounced inactivation of tumor suppressor genes by comparison. DNA methylation-based analysis of the tumor microenvironment by MethylCIBERSORT yielded two, prognostically relevant clusters (IC1 and IC2) with specific cellular composition and mutational spectra. Further, the transcriptional subgroups of BPDCN (C1 and C2) differ by DNA methylation signatures in interleukin/inflammatory signaling genes but also by higher transcription factor activity of JAK-STAT and NFkB signaling in C2 in contrast to an EZH2 dependence in C1-BPDCN. Our integrative characterization of BPDCN offers novel molecular insights and potential diagnostic applications.

MicroRNA expression and JAK2 allele burden in bone marrow trephine biopsies of polycythemia vera, essential thrombocythemia and early primary myelofibrosis.

BACKGROUND/AIMS: MicroRNAs (miRNAs) play an important role in cellular differentiation and cancer pathogenesis. However, their role in promoting the malignant phenotype of myeloproliferative diseases and their importance for differential diagnosis of early-stage chronic myeloproliferative diseases (CMPDs) remains widely obscure. METHODS: In this study, we systematically evaluated the differential expression of miRNAs previously described to be associated with myelopoiesis and myeloproliferative pathogenesis by quantitative RT-PCR in polycythemia vera, essential thrombocythemia, early primary myelofibrosis (PMF) and normal hematopoiesis. Our goal was to establish certain miRNAs as potential markers for CMPDs to facilitate the differentiation between these diseases and to further investigate molecular differences between the subtypes of myeloproliferative neoplasia. RESULTS: An aberrant expression of miRNAs 10a and 150 could be demonstrated for essential thrombocythemia and PMF as well as for polycythemia vera and PMF, respectively. The expression of miR-150 could further be shown to correlate with both JAK2 allele burden and peripheral blood counts. CONCLUSION: Thus, the miRNAs investigated in this study seem to be potential marker oncomiRs in the differential diagnosis of CMPDs and possibly hold potential for the elucidation of a JAK2-independent mechanism of pathogenesis.

Novel insights into the pathogenesis of follicular lymphoma by molecular profiling of localized and systemic disease forms.

Knowledge on the pathogenesis of FL is mainly based on data derived from advanced/systemic stages of FL (sFL) and only small cohorts of localized FL (lFL) have been characterized intensively so far. Comprehensive analysis with profiling of somatic copy number alterations (SCNA) and whole exome sequencing (WES) was performed in 147 lFL and 122 sFL. Putative targets were analyzed for gene and protein expression. Overall, lFL and sFL, as well as BCL2 translocation-positive (BCL2+) and -negative (BCL2-) FL showed overlapping features in SCNA and mutational profiles. Significant differences between lFL and sFL, however, were detected for SCNA frequencies, e.g., in 18q-gains (14% lFL vs. 36% sFL; p = 0.0003). Although rare in lFL, gains in 18q21 were associated with inferior progression-free survival (PFS). The mutational landscape of lFL and sFL included typical genetic lesions. However, ARID1A mutations were significantly more often detected in sFL (29%) compared to lFL (6%, p = 0.0001). In BCL2 + FL mutations in KMT2D, BCL2, ABL2, IGLL5 and ARID1A were enriched, while STAT6 mutations more frequently occurred in BCL2- FL. Although the landscape of lFL and sFL showed overlapping features, molecular profiling revealed novel insights and identified gains in 18q21 as prognostic marker in lFL.

Immunoblastic morphology but not the immunohistochemical GCB/nonGCB classifier predicts outcome in diffuse large B-cell lymphoma in the RICOVER-60 trial of the DSHNHL.

The survival of diffuse large B-cell lymphoma patients varies considerably, reflecting the molecular diversity of tumors. In view of the controversy whether cytologic features, immunohistochemical markers or gene expression signatures may capture this molecular diversity, we investigated which features provide prognostic information in a prospective trial in the R-CHOP treatment era. Within the cohort of DLBCLs patients treated in the RICOVER-60 trial of the German High-Grade Lymphoma Study Group (DSHNHL), we tested the prognostic impact of IB morphology in 949 patients. The expression of immunohistochemical markers CD5, CD10, BCL2, BCL6, human leukocyte antigen (HLA)-DR, interferon regulatory factor-4/multiple myeloma-1 (IRF4/MUM1), and Ki-67 was assessed in 506 patients. Expression of the immunohistochemical markers tested was of modest, if any, prognostic relevance. Moreover, the Hans algorithm using the expression patterns of CD10, BCL6, and interferon regulatory factor-4/multiple myeloma-1 failed to show prognostic significance in the entire cohort as well as in patient subgroups. IB morphology, however, emerged as a robust, significantly adverse prognostic factor in multivariate analysis, and its diagnosis showed a good reproducibility among expert hematopathologists. We conclude, therefore, that IB morphology in DLBCL is likely to capture some of the adverse molecular alterations that are currently not detectable in a routine diagnostic setting, and that its recognition has significant prognostic power.