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Supplementary Table S1. Sanger validated variants. Supplementary Table S2. Mutations in HSTL driver genes. Supplementary Table S3. Other mutations identified by exome sequencing. Supplementary Table S4. Copy number of HSTL patients and cell lines. Supplementary Table S5. Clinical and pathological characteristics of HSTL patients. Supplementary Tables S6, S7. Comparison to HSTL clinical data in the literature. Supplementary Table S8. Mutational frequencies in other lymphomas. Supplementary Table S9. HSTL mutations in other lymphoma driver genes. Supplementary Table S10. Gene set enrichment analysis of DERL2 SETD2 shRNA.

Supplementary Figure S1. Sanger sequencing chromatograms. Supplementary Figure S2. Cancer cell fraction for driver genes. Supplementary Figure S3. Ideogram with chromosome 7 alterations. Supplementary Figure S4. Examples of Exome Copy Number. Supplementary Figure S5. Exploratory Kaplan-Meier plots for clinical covariates. Supplementary Figure S6. Exploratory Kaplan-Meier plots for molecular covariates. Supplementary Figure S7. Sanger and exome sequencing validation of SETD2 biallelic mutation in one HSTL case. Supplementary Figure S8. SETD2 expression in mutant vs. wildtype cases. Supplementary Figure S9. Mutual exclusivity of STAT5B, PIK3CD, and STAT3 mutations.

Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is a rare extranodal lymphoma subtype. This retrospective study elucidates the currently unknown genetic background of a large clinically well-annotated cohort of DLBCLwith osseous localizations (O-DLBCL), including PB-DLBCL. A total of 103 patients with O-DLBCL were included and compared with 63 (extra)nodal non-osseous (NO)-DLBCLs with germinal center B-cell phenotype (NO-DLBCL-GCB). Cell-of-origin was determined by immunohistochemistry and gene-expression profiling (GEP) using (extended)-Nano-String/Lymph2Cx analysis. Mutational profileswere identifiedwith targeted next-generation deep sequencing, including 52 B-cell lymphoma-relevant genes. O-DLBCLs, including 34 PB-DLBCLs, were predominantly classified as GCB phenotype based on immunohistochemistry (74%) and NanoString analysis (88%). Unsupervised hierarchical clustering of an extended-NanoString/Lymph2Cx revealed significantly different GEP clusters for PB-DLBCL as opposed to NO-DLBCL-GCB (P < .001). Expression levels of 23 genes of 2 different targeted GEP panels indicated a centrocyte-like phenotype for PB-DLBCL, whereas NO-DLBCL-GCB exhibited a centroblast-like constitution. PB-DLBCL had significantly more frequent mutations in four GCB-associated genes (ie, B2M, EZH2, IRF8, TNFRSF14) comparedwithNO-DLBCL-GCB (P = .031, P = .010, P = .047, and P = .003, respectively). PB-DLBCL, with its corresponding specific mutational profile, was significantly associated with a superior survival compared with equivalent Ann Arbor limited-stage I/II NO-DLBCL-GCB (P = .016). This study is the first to show that PB-DLBCL is characterized by a GCB phenotype, with a centrocyte-like GEP pattern and a GCB-associated mutational profile (both involved in immune surveillance) and a favorable prognosis. These novel biology-associated features provide evidence that PB-DLBCL represents a distinct extranodal DLBCL entity, and its specific mutational landscape offers potential for targeted therapies (eg, EZH2 inhibitors).

Mediastinal gray zone lymphoma (MGZL) has immunopathologic features between classical Hodgkin lymphoma (cHL) and primary mediastinal thymic B-cell lymphoma (PMBL), leading to uncertainty regarding its biological relationship to these entities. We performed gene expression profiling from patients with MGZL (20), cHL (18), and PMBL (17) and show MGZL clusters between cHL and PMBL. Expression signatures reveal germinal B-cell and IFN regulatory factor 4 (IRF4) signatures were relatively low in MGZL and cHL compared with PMBL, indicating downregulation of the B-cell program in MGZL, a hallmark of cHL. T-cell and macrophage signatures were higher in MGZL and cHL compared with PMBL, consistent with infiltrating immune cells, which are found in cHL. The NFκB signature was higher in MGZL than PMBL, and like cHL, MGZL and PMBL express NFκB inducing kinase (NIK), indicating noncanonical signaling. These findings indicate that while MGZL has distinctive clustering, it is biologically closer to cHL. Significance: We performed comparative gene expression analysis of MGZL, cHL, and PMBL and show most MGZL cases are biologically closer to cHL. MGZL has significantly higher tumor cell density than cHL and greater NFκB activation compared with PMBL, which may explain its greater treatment resistance compared with cHL and PMBL. This article is highlighted in the In This Issue feature, p. 127

Nodal peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) with cytotoxic phenotype is overall rare, with most reports coming from Asia. Given its elusive pathobiology, we undertook a clinicopathological and molecular study of 54 Western patients diagnosed with PTCL, NOS expressing cytotoxic molecules, within a lymph node. More commonly males (M/F-2,6/1) with median age of 60 years were affected. Besides lymphadenopathy, 87% of patients had ≥1 involved extranodal site. High-stage disease (III-IV), International Prognostic Index2, B symptoms, LDH level, and cytopenia(s) were observed in 92, 63, 67, 78, and 66% of cases, respectively. Ten patients had a history of B-cell malignancies, one each of myeloid neoplasm, breast or prostate cancer, and 4 others had underlying immune disorders. Most patients (70%) died, mostly of disease, with a median overall survival of 12.7 months. Immunophenotypically, the neoplastic lymphocytes were T-cell receptor (TCR) αβ + (47%), TCR-silent (44%) or TCRγδ+ (10%), commonly CD8 + (45%) or CD4-CD8- (32%). All except one had an activated cytotoxic profile, and 95% were subclassified into PTCL-TBX21 subtype based on CXCR3, TBX21, and GATA3 expression pattern. Seven patients (13%) disclosed EBER + tumor cells. Targeted DNA deep-sequencing (33 cases) and multiplex ligation-dependent reverse transcription-polymerase chain reaction assay (43 cases) identified frequent mutations in epigenetic modifiers (73%), including TET2 (61%) and DNMT3A (39%), recurrent alterations affecting the TCR (36%) and JAK/STAT (24%) signaling pathways and TP53 mutations (18%). Fusion transcripts involving VAV1 were identified in 6/43 patients (14%). Patients with nodal cytotoxic PTCL, NOS have an aggressive behavior and frequently present in a background of impaired immunity, although the association with Epstein-Barr virus is rare. The recurrent alterations in genes involved in DNA methylation together with genes related to cytokine or TCR signaling, suggest that co-operation of epigenetic modulation with cell-signaling pathways plays a critical role in the pathogeny of these lymphomas.

We report the case of a 23-year-old man with nodal EMH (extramedullary hematopoiesis) occurring during treatment for a stage IIA "gray-zone" lymphoma. Although it is often related to myeloproliferative bone marrow disease, benign etiologies such as lenograstim treatment after chemotherapy can also induce EMH and be responsible for false-positive F-FDG PET/CT examinations. In this respect, GLUT overexpression in hematopoietic lineages and macrophages of the inflammatory environment are responsible for increased F-FDG uptake. Histopathologic confirmation of new hypermetabolic lesions on follow-up PET/CT may be required when the new lesions do not conform with the treatment responses in the preexisting lesions.

Histiocytic sarcoma is a rare malignant neoplasm that may occur de novo or in the context of a previous hematologic malignancy or mediastinal germ cell tumor. Here, we performed whole exome sequencing and RNA-sequencing (RNA-Seq) on 21 archival cases of primary histiocytic sarcoma. We identified a high number of genetic alterations within the RAS/RAF/MAPK pathway in 21 of 21 cases, with alterations in NF1 (6 of 21), MAP2K1 (5 of 21), PTPN11 (4 of 21), BRAF (4 of 21), KRAS (4 of 21), NRAS (1 of 21), and LZTR1 (1 of 21), including single cases with homozygous deletion of NF1, high-level amplification of PTPN11, and a novel TTYH3-BRAF fusion. Concurrent NF1 and PTPN11 mutations were present in 3 of 21 cases, and 5 of 7 cases with alterations in NF1 and/or PTPN11 had disease involving the gastrointestinal tract. Following unsupervised clustering of gene expression data, cases with NF1 and/or PTPN11 abnormalities formed a distinct tumor subgroup. A subset of NF1/PTPN11 wild-type cases had frequent mutations in B-cell lymphoma associated genes and/or clonal IG gene rearrangements. Our findings expand the current understanding of the molecular pathogenesis of this rare tumor and suggest the existence of a distinct subtype of primary histiocytic sarcoma characterized by NF1/PTPN11 alterations with predilection for the gastrointestinal tract.

Plasmablastic lymphoma (PBL) is an aggressive B-cell lymphoma with an immunoblastic/large-cell morphology and terminal B-cell differentiation. The differential diagnosis from Burkitt lymphoma, plasma cell myeloma and some variants of diffuse large B-cell lymphoma may be challenging because of the overlapping morphological, genetic and immunophenotypic features. Furthermore, the genomic landscape in PBL is not well known. To characterize the genetic and molecular heterogeneity of these tumors, we investigated 34 cases of PBL using an integrated approach, including fluorescence in situ hybridization, targeted sequencing of 94 B-cell lymphoma-related genes, and copy-number arrays. PBL were characterized by high genetic complexity including MYC translocations (87%), gains of 1q21.1-q44, trisomy 7, 8q23.2- q24.21, 11p13-p11.2, 11q14.2-q25, 12p and 19p13.3-p13.13, losses of 1p33, 1p31.1-p22.3, 13q and 17p13.3-p11.2, and recurrent mutations of STAT3 (37%), NRAS and TP53 (33%), MYC and EP300 (19%) and CARD11, SOCS1 and TET2 (11%). Pathway enrichment analysis suggested a cooperative action between MYC alterations and MAPK (49%) and JAK-STAT (40%) signaling pathways. Of note, Epstein-Barr virus (EBV)-negative PBL cases had higher mutational and copy-number load and more frequent TP53, CARD11 and MYC mutations, whereas EBVpositive PBL tended to have more mutations affecting the JAK-STAT pathway. In conclusion, these findings further unravel the distinctive molecular heterogeneity of PBL identifying novel molecular targets and the different genetic profile of these tumors in relation to EBV infection.

The oncogenic events involved in breast implant-associated anaplastic large cell lymphoma (BI-ALCL) remain elusive. To clarify this point, we have characterized the genomic landscape of 34 BI-ALCLs (15 tumor and 19 in situ subtypes) collected from 54 BI-ALCL patients diagnosed through the French Lymphopath network. Whole-exome sequencing (n = 22, with paired tumor/germline DNA) and/or targeted deep sequencing (n = 24) showed recurrent mutations of epigenetic modifiers in 74% of cases, involving notably KMT2C (26%), KMT2D (9%), CHD2 (15%), and CREBBP (15%). KMT2D and KMT2C mutations correlated with a loss of H3K4 mono- and trimethylation by immunohistochemistry. Twenty cases (59%) showed mutations in ≥1 member of the JAK/STAT pathway, including STAT3 (38%), JAK1 (18%), and STAT5B (3%), and in negative regulators, including SOCS3 (6%), SOCS1 (3%), and PTPN1 (3%). These mutations were more frequent in tumor-type samples than in situ samples (P = .038). All BI-ALCLs expressed pSTAT3, regardless of the mutational status of genes in the JAK/STAT pathway. Mutations in the EOMES gene (12%) involved in lymphocyte development, PI3K-AKT/mTOR (6%), and loss-of-function mutations in TP53 (12%) were also identified. Copy-number aberration (CNA) analysis identified recurrent alterations, including gains on chromosomes 2, 9p, 12p, and 21 and losses on 4q, 8p, 15, 16, and 20. Regions of CNA encompassed genes involved in the JAK/STAT pathway and epigenetic regulators. Our results show that the BI-ALCL genomic landscape is characterized by not only JAK/STAT activating mutations but also loss-of-function alterations of epigenetic modifiers.

Cloud service providers are often prohibited from accessing the content of tenant VMs, yet current techniques for monitoring attacks and unauthorized activities rely on virtual machine introspection (VMI). While the introspections are useful for narrowing down the semantic gap between the status observed at the hypervisor-level and that seen in a VM, they potentially reveal the sensitive information of a tenant stored in the machine. In this paper, we aim to infer specific program activities in a VM without VMI methods, where our approach has to solve the strong semantic gap problem. We introduce Infermatic, a system that utilizes only hypervisor-level features and supervised machine learning methods to infer program behaviors in a VM. Using the classifiers trained by Infermatic, we can also bridge the strong semantic gap by systematically identifying the semantic links between our hypervisor features and selected program behaviors. In evaluations, we demonstrate that the hypervisor features are effective in isolating program activities and do so with an average accuracy of 0.875 (AUC) for the 24 behaviors that we have identified. In addition, our statistical models (or trained classifiers) can identify the hypervisor features that accurately characterize selected program behaviors when they involve lower-level operations. We further extend Infermatic’s ability to detect program behaviors to other security applications—we present a malicious VM detector for the cloud that achieves an average detection of 0.817 (AUC). Our detector shows the hypervisor features are resilient against evasion attacks even when an attacker can reduce the number of available features to the system. Moreover, we present that the detector can operate in a scalable manner by identifying a malicious VM even when the VM under inspection is collocated with other VM’s operating under workloads.

Starting from the directing and fluid concentration effect in a cylindrical enclosure, it was developed, at laboratory scale, an integrated installation to be use in coastal areas which use 3 natural resources for the production of electricity within the same system. Initially, the wind turbine, which is an integral part of this system, was provided with trapezoidal blades. In order to obtain higher power, other types of blades have been studied and proposed, whose geometry is inspired by nature. As a result of the tests carried out at the pilot station, it was demonstrated that if bioengineering models are used, the rotation speed of the blades increases by approx. 37% compared to trapezoidal ones.

In order to ensure a sustainable development by substantially reducing human contribution to accentuating the greenhouse effect phenomenon and exhausting natural resources, it was necessary to develop various installations for capturing, storing and transforming the energy produced by renewable sources into electricity. At the same time, efficient resource use is one of the most important prerequisites for sustainable economic growth and the transformation of waste into secondary raw materials forms the basis for systems that promote the circular economy. In this sense, it is necessary to research and apply new technologies for the integration of recycled materials into complex systems of green energy production. The present paper describes the preliminary results obtained from the laboratory tests which involved the use of recyclable materials in order to produce electricity based on solar energy.In order to ensure a sustainable development by substantially reducing human contribution to accentuating the greenhouse effect phenomenon and exhausting natural resources, it was necessary to develop various installations for capturing, storing and transforming the energy produced by renewable sources into electricity. At the same time, efficient resource use is one of the most important prerequisites for sustainable economic growth and the transformation of waste into secondary raw materials forms the basis for systems that promote the circular economy. In this sense, it is necessary to research and apply new technologies for the integration of recycled materials into complex systems of green energy production. The present paper describes the preliminary results obtained from the laboratory tests which involved the use of recyclable materials in order to produce electricity based on solar energy.

Nodal follicular helper T-cell-derived lymphoproliferations (specifically the less common peripheral T-cell lymphomas of follicular type) exhibit a spectrum of histologic features that may mimic reactive hyperplasia or Hodgkin lymphoma. Even though angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma of follicular type share a common biologic origin from follicular helper T-cells and their morphology has been well characterized, flow cytometry of peripheral T-cell lymphomas of follicular type has not been widely discussed as a tool for identifying this reactive hyperplasia/Hodgkin lymphoma mimic. We identified 10 peripheral T-cell lymphomas of follicular type with available flow cytometry data from five different institutions, including two cases with peripheral blood evaluation. For comparison, we examined flow cytometry data for 8 classical Hodgkin lymphomas (including 1 lymphocyte-rich classical Hodgkin lymphoma), 15 nodular lymphocyte predominant Hodgkin lymphomas, 15 angioimmunoblastic T-cell lymphomas, and 26 reactive nodes. Lymph node histology and flow cytometry data were reviewed, specifically for the presence of a CD3(-/dim)CD4(+) aberrant T-cell population (described in angioimmunoblastic T-cell lymphomas), besides other T-cell aberrancies. Nine of 10 (90%) peripheral T-cell lymphomas of follicular type showed a CD3(-/dim)CD4(+) T-cell population constituting 29.3% (range 7.9-62%) of all lymphocytes. Five of 10 (50%) had nodular lymphocyte predominant Hodgkin lymphoma or lymphocyte-rich classical Hodgkin lymphoma-like morphology with scattered Hodgkin-like cells that expressed CD20, CD30, CD15, and MUM1. Three cases had a nodular growth pattern and three others exhibited a perifollicular growth pattern without Hodgkin-like cells. Epstein-Barr virus was positive in 1 of 10 cases (10%). PCR analysis showed clonal T-cell receptor gamma gene rearrangement in all 10 peripheral T-cell lymphomas of follicular type. By flow cytometry, 11 of 15 (73.3%) angioimmunoblastic T-cell lymphomas showed the CD3(-/dim)CD4(+) population (mean: 19.5%, range: 3-71.8%). Using a threshold of 3% for CD3(-/dim)CD4(+) T cells, all 15 nodular lymphocyte predominant Hodgkin lymphoma controls and 8 classical Hodgkin lymphomas were negative (Mann-Whitney P=0.01, F-PTCL vs Hodgkin lymphomas), as were 25 of 26 reactive lymph nodes. The high frequency of CD3(-/dim)CD4(+) aberrant T cells is similar in angioimmunoblastic T-cell lymphomas and peripheral T-cell lymphomas of follicular type, and is a useful feature in distinguishing peripheral T-cell lymphomas of follicular type from morphologic mimics such as reactive hyperplasia or Hodgkin lymphoma.

Introduction: Diffuse large B-cell lymphoma (DLBCL) is an aggressive and heterogeneous disease characterized by recurrent genetic alterations. Several adverse prognostic factors are well known as International Prognostic Index (IPI) parameters or MYC and BCL2 and/or BCL6 gene rearrangements (High-Grade B-cell Lymphoma double/triple hit, HGBL-DH/TH, according to the 2016 WHO classification). Other factors are controversial as previous history of indolent lymphoma, cell of origin (COO), co-expression of MYC and BCL2 proteins (double expressor (DE) status), MYC partner gene if rearranged. The aim of this study is to describe a « real life » cohort of patients treated in our institution for aggressive (non-Burkitt) B-cell lymphoma and to evaluate the prognostic impact of phenotypic and genetic alterations. Methods: We collected clinical and histological characteristics of patients uniformly treated between January 2009 and June 2017 with rituximab R-CHOP/CHOP-like chemotherapy. Treatment was reinforced with high dose methotrexate in case of central nervous system (CNS) localization or HGBL subtype. All tumor samples were analysed for MYC and BCL2 protein expression by immunohistochemistry. BCL2, BCL6 and MYC break were analysed by Interphase Fluorescence In Situ Hybridization (FISH) with breakapart probes. When MYC was rearranged MYC partner gene was analysed with double fusion probes (MYC/IgH, MYC/IgL, MYC/IgK). Positron Emission Tomography (PET scanner) was performed with maximal Standardized Uptake Value (SUV max) at baseline in all patients except 7. Results: 242 patients were studied. Baseline characteristics were: median age: 61 y (18-88), IPI 3-5: 49.6%, CNS localization: 6.6%. With a median follow-up of 4.4 years, 5y-overall survival (OS) and 5y-progression free survival (PFS) were 72% (66.0-78.5) and 65% (58.5-71.3), respectively. SUV max at baseline was 17,1 (minimum value 2,4 - maximal value 39,3).Histological diagnoses were DLBCL-not otherwise specified (NOS): 57%, transformed DLBCL: 26%, HGBL: 7.9%, primary mediastinal B-cell lymphoma (PMBL): 4.1% and others: 5%. Using Hans algorithm, 48.8% were classified as germinal center (GC), 47.9% as non-GC, 3.3% could not be evaluated and 38% were DE. MYC rearrangement was detected in 36 cases (14.9%) with an immunoglobulin partner gene (IgH, IgL or IgK) in 24 (77.4%) of 31 evaluable cases. BCL2 and BCL6 rearrangement were observed in 45 cases (18.6%) and 62 (25.6%) cases respectively. Fifteen cases were HGBL DH/TH including 7 DH MYC/BCL2, 5 DH MYC/BCL6 and 3 TH MYC/BCL2/BCL6. Four cases were HGBL-NOS. IPI score 3-5 (p Conclusions: This monocentric study in a large cohort of aggressive B-cell lymphoma patients treated in real life conditions confirms previous reports on the negative prognostic impact of DE status, MYC and BCL2 translocations and HGBL subtype. These genetic and immuno-histological characteristics should have implications in the design and interpretation of future clinical trials. Disclosures Le Bras: Takeda: Research Funding; Pfizer: Other: Travel grant; Jansen: Other: Travel grant. Belhadj:Celgene: Other: personal fees from Celgene, personal fees from Amgen, personal fees from Takeda, personal fees from Janssen, outside the submitted work. Haioun:servier: Honoraria; amgen: Honoraria; janssen cilag: Consultancy; takeda: Consultancy; gilead: Consultancy; novartis: Honoraria; celgene: Honoraria; roche: Consultancy; celgene: Consultancy.

Human herpes virus 6 (HHV-6) is a member of the β-herpesvirinae subfamily. Most people acquire HHV-6 primary infection early in life and reactivation may occur, most often in immunocompromised individuals, leading to various clinical manifestations. HHV-6 infected cells may be identified in lymph nodes in both reactive and neoplastic conditions. Cases were retrieved from the hematopathology consultation service archives at National Institutes of Health from 2003 to 2017 in which infection by HHV-6 had been documented by immunohistochemical stains to HHV-6 gp60/110 envelope glycoprotein. Five cases of reactive lymphadenitis and 3 cases of lymphoma; 2 angioimmunoblastic T-cell lymphoma and 1 classic Hodgkin lymphoma, positive for HHV-6 were identified. The reactive lymph nodes showed marked paracortical hyperplasia and admixed large atypical lymphoid cells exhibiting pleomorphic nuclei, vesicular chromatin, and prominent eosinophilic intranuclear inclusions. Vascular proliferation and necrosis were also present, raising suspicion of peripheral T-cell lymphoma. The 3 cases of lymphoma showed similar viral inclusions, in addition to the characteristic features diagnostic of the lymphoma. Staining for HHV-6 was positive with a membranous and Golgi pattern and was restricted to cells with evident inclusions on hematoxylin and eosin. HHV-6 infected cells were positive for CD3 and CD4. HHV-6 lymphadenitis can present with morphologic atypia creating a diagnostic pitfall for lymphoma. In such cases, careful attention to the characteristic viral inclusions can lead to immunohistochemical analysis highlighting the replicating virus. In cases of lymphoma, identification of the inclusions is key in detecting the associated infection as well as in avoiding misinterpretation of the lymphoma subtype.

Few studies have reported Epstein-Barr virus-positive (EBV(+)) large B-cell lymphomas (LBCLs) in young patients without immunodeficiency. We identified 46 such cases in patients ≤45 years of age and analyzed the clinical and pathological characteristics. EBV(+) LBCLs affected predominantly males (male:female = 3.6:1), with a median age of 23 years (range, 4-45 years). All patients presented with lymphadenopathy and 11% also had extranodal disease. Morphologically, 3 patterns were identified: T-cell/histiocyte-rich large B-cell lymphoma-like (n = 36), gray zone lymphoma (n = 7), and diffuse LBCL-not otherwise specified (n = 3). Tumor cells (EBV(+) in >90% of cells) expressed B-cell antigens, were often CD30 and PD-L1 positive, and showed a nongerminal center immunophenotype. A total of 93% expressed EBV latency type II and 7% latency type III. Indoleamine 2,3-dioxygenase was expressed on background accessory cells. The most common treatment regimen was rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (58%), with local radiation therapy added in 21%. With a median follow-up of 22 months, 82% of patients are in clinical remission and only 8% died of disease. Younger patients achieved a significantly higher overall survival than prior series of EBV(+) LBCLs reported in the elderly (P < .0001). In conclusion, EBV(+) LBCLs are not restricted to the elderly. Young patients present with nodal disease and have a good prognosis.

Mutations in the JAK/STAT and RAS signaling pathways are common in intestinal T-cell lymphomas

Background Intestinal differentiation of primary mucinous adenocarcinoma of the uterine corpus is exceedingly rare in comparison to the approximately 25% rate in endocervical and ovarian mucinous carcinoma. Additionally, little is known about the related genetic and epigenetic alterations, even though large-scale molecular characterisation of the different types of endometrial cancer took place in the TCGA project along the entities defined by the recent WHO classification. Case presentation We present a 62-year-old patient harbouring a primary mucinous carcinoma of the uterine corpus with a morphological resemblance to mucinous colorectal adenocarcinoma. The intestinal differentiation was substantiated by CDX2 and CK20 positivity in the absence of PAX8, p16, WT1, p53, ER, PgR, AFP, SALL4 and Glypican3. A high MSI status with MLH1 hypermethylation was revealed by molecular testing. Conclusion Intestinal differentiation of mucinous adenocarcinoma of the endometrium is a unique observation. Besides morphology, it obviously can share molecular features of sporadic MSI colorectal cancers. It can be speculated that either CDX2 positive morula formation or intestinal metaplasia of the endometrium as rare conditions might be the origin of carcinogenesis for this type II endometrial cancer. Both conditions were not detectable in this case. Of note, categorising endometrial cancers in genetic subgroups like MSI high cancers alone might lead to the integration of likewise morphologically different tumours like the case presented here with intestinal differentiation. Hence, careful genotype-phenotype correlations are warranted for studies of mucinous adenocarcinoma of the endometrium. Electronic supplementary material The online version of this article (doi:10.1186/s13000-017-0629-0) contains supplementary material, which is available to authorized users.

Activating Janus kinase (JAK) and signal transducer and activator of transcription (STAT) mutations have been discovered in many T-cell malignancies, including anaplastic lymphoma kinase (ALK)- anaplastic large cell lymphomas (ALCLs). However, such mutations occur in a minority of patients. To investigate the clinical application of targeting JAK for ALK- ALCL, we treated ALK- cell lines of various histological origins with JAK inhibitors. Interestingly, most exogenous cytokine-independent cell lines responded to JAK inhibition regardless of JAK mutation status. JAK inhibitor sensitivity correlated with the STAT3 phosphorylation status of tumor cells. Using retroviral shRNA knockdown, we have demonstrated that these JAK inhibitor-sensitive cells are dependent on both JAK1 and STAT3 for survival. JAK1 and STAT3 gain-of-function mutations were found in some, but not all, JAK inhibitor-sensitive cells. Moreover, the mutations alone cannot explain the JAK1/STAT3 dependency, given that wild-type JAK1 or STAT3 was sufficient to promote cell survival in the cells that had either JAK1or STAT3 mutations. To investigate whether other mechanisms were involved, we knocked down upstream receptors GP130 or IL-2Rγ. Knockdown of GP130 or IL-2Rγ induced cell death in selected JAK inhibitor-sensitive cells. High expression levels of cytokines, including IL-6, were demonstrated in cell lines as well as in primary ALK- ALCL tumors. Finally, ruxolitinib, a JAK1/2 inhibitor, was effective in vivo in a xenograft ALK- ALCL model. Our data suggest that cytokine receptor signaling is required for tumor cell survival in diverse forms of ALK- ALCL, even in the presence of JAK1/STAT3 mutations. Therefore, JAK inhibitor therapy might benefit patients with ALK- ALCL who are phosphorylated STAT3 .

Aggressive natural killer cell leukemia (ANKL) is a systemic NK-cell neoplasm, almost always associated with Epstein-Barr virus (EBV). Rare cases of EBV-negative ANKL have been described, and some reports suggested more indolent behavior. We report the clinicopathologic, immunophenotypic, and molecular characteristics of 7 EBV-negative ANKL. All patients were adults, with a median age of 63 years (range 22 to 83 y) and an M:F ratio of 2.5:1. Five patients were White, 1 Black, and 1 Asian. All patients presented acutely, with fever (6/7), cytopenias (6/7), and splenomegaly (4/7). Four patients had lymphadenopathy, 4 had extranodal disease. Bone marrow involvement was present in 5, with hemophagocytosis in 3. Peripheral blood was involved in 5 with the neoplastic cells containing prominent azurophilic granules. By immunohistochemistry and/or flow cytometry, the tumor cells lacked surface CD3 and were positive for CD56 (7/7), CD2 (5/5), CD8 (3/7), CD30 (4/5), and granzyme-B (6/6). They were negative for CD4, CD5, βF1, TCRγ, LMP1, and EBV-encoded RNA. Polymerase chain reaction for TCRG clonality was polyclonal. Mutational analysis revealed missense mutations in the STAT3 gene in both cases studied. Median survival was 8 weeks from the onset of disease. One patient received allogeneic bone marrow transplant and is alive with no disease (follow-up 15 mo). EBV-negative ANKL exists but is rare. It tends to occur in older patients and is indistinguishable clinically and pathologically from EBV-positive ANKL, with a similar fulminant clinical course. The high prevalence of Asian patients seen with EBV-positive disease seems less evident with EBV-negative cases.

Hepatosplenic T-cell lymphoma (HSTL) is a rare and lethal lymphoma; the genetic drivers of this disease are unknown. Through whole-exome sequencing of 68 HSTLs, we define recurrently mutated driver genes and copy-number alterations in the disease. Chromatin-modifying genes, including SETD2, INO80, and ARID1B, were commonly mutated in HSTL, affecting 62% of cases. HSTLs manifest frequent mutations in STAT5B (31%), STAT3 (9%), and PIK3CD (9%), for which there currently exist potential targeted therapies. In addition, we noted less frequent events in EZH2, KRAS, and TP53. SETD2 was the most frequently silenced gene in HSTL. We experimentally demonstrated that SETD2 acts as a tumor suppressor gene. In addition, we found that mutations in STAT5B and PIK3CD activate critical signaling pathways important to cell survival in HSTL. Our work thus defines the genetic landscape of HSTL and implicates gene mutations linked to HSTL pathogenesis and potential treatment targets. Significance: We report the first systematic application of whole-exome sequencing to define the genetic basis of HSTL, a rare but lethal disease. Our work defines SETD2 as a tumor suppressor gene in HSTL and implicates genes including INO80 and PIK3CD in the disease. Cancer Discov; 7(4); 369–79. ©2017 AACR. See related commentary by Yoshida and Weinstock, p. 352. This article is highlighted in the In This Issue feature, p. 339

Anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a CD30-positive T-cell non-Hodgkin lymphoma that morphologically resembles ALK-positive ALCL but lacks chromosomal rearrangements of the ALK gene. The genetic and clinical heterogeneity of ALK-negative ALCL has not been delineated. We performed immunohistochemistry and fluorescence in situ hybridization on 73 ALK-negative ALCLs and 32 ALK-positive ALCLs and evaluated the associations among pathology, genetics, and clinical outcome. Chromosomal rearrangements of DUSP22 and TP63 were identified in 30% and 8% of ALK-negative ALCLs, respectively. These rearrangements were mutually exclusive and were absent in ALK-positive ALCLs. Five-year overall survival rates were 85% for ALK-positive ALCLs, 90% for DUSP22-rearranged ALCLs, 17% for TP63-rearranged ALCLs, and 42% for cases lacking all 3 genetic markers (P < .0001). Hazard ratios for death in these 4 groups after adjusting for International Prognostic Index and age were 1.0 (reference group), 0.58, 8.63, and 4.16, respectively (P = 7.10 × 10−5). These results were similar when restricted to patients receiving anthracycline-based chemotherapy, as well as to patients not receiving stem cell transplantation. Thus, ALK-negative ALCL is a genetically heterogeneous disease with widely disparate outcomes following standard therapy. DUSP22 and TP63 rearrangements may serve as predictive biomarkers to help guide patient management.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and classical Hodgkin lymphoma (CHL) are classified separately because of their distinct clinical and pathologic features. Whereas Epstein-Barr virus (EBV) is detected in the neoplastic cells of 25% to 70% of CHL, NLPHL is generally considered to be EBV(-). We assessed EBV status in 302 pediatric and adult cases of NLPHL. A total of 145 pediatric (age 18 y or younger) and 157 adult cases of NLPHL were retrieved from 3 North American centers and tested for EBV by in situ hybridization (EBV-encoded small RNA). Clinical and pathologic features were analyzed. Five (3.4%) pediatric and 7 (4.5%) adult NLPHL cases contained EBV(+) lymphocyte-predominant (LP) cells. Although all 12 cases met the criteria for diagnosis of NLPHL, atypical features were present, including capsular fibrosis, atrophic germinal centers, and pleomorphic or atypical LP cells. CD20 and OCT-2 were strongly and diffusely positive in all except 1 case. However, PAX5 and CD79a were weak and/or variable in 7/8 and 6/6 cases tested, respectively. EBV(+) cases were more likely to be CD30(+) (75%) compared with EBV(-) cases (25%) (P=0.0007); CD15 was negative in all cases. Our results show that EBV(+) LP cells may occur in NLPHL. Distinguishing EBV(+) NLPHL from CHL can be challenging, as EBV(+) NLPHL can have partial expression of CD30 and weak PAX5 staining as well as pleomorphic-appearing LP cells. However, the overall appearance and maintenance of B-cell phenotype, with strong and diffuse CD20 and OCT-2 expression, support the diagnosis of NLPHL in these cases.

A discordant lymphoma occurs where 2 distinct histologic subtypes coexist in at least 2 separate anatomic sites. Histologic discordance is most commonly observed between the bone marrow (BM) and lymph nodes (LNs), where typically aggressive lymphoma is found in a LN biopsy with indolent lymphoma in a BM biopsy. Although the diagnosis of discordance relied heavily on histopathology alone in the past, the availability of flow cytometry and molecular studies have aided the identification of this entity. The true prevalence and clinical ramifications of discordance remain controversial as available data are principally retrospective, and there is therefore little consensus to guide optimal management strategies. In this review, we examine the available literature on discordant lymphoma and its outcome, and discuss current therapeutic approaches. Future studies in discordant lymphoma should ideally focus on a large series of patients with adequate tissue samples and incorporate molecular analyses.

Systemic anaplastic large cell lymphomas (ALCLs) are classified into ALK-positive and ALK-negative types. We recently reported that ALK-negative ALCLs are genetically heterogenous. The largest subset, representing 30% of cases, had rearrangements of the DUSP22 locus. These cases had favorable outcomes similar to ALK-positive ALCL, and superior to other ALK-negative ALCLs. Here, we examined the morphologic features of these cases in more detail. First, we conducted blinded review of hematoxylin and eosin slides of 108 ALCLs from our previous study, scoring cases for the presence of 3 histologic patterns and 5 cell types. Cases then were unblinded and re-reviewed to understand these features further. DUSP22-rearranged ALCLs were more likely than other ALK-negative ALCLs to have so-called doughnut cells (23% vs. 5%; P = 0.039), less likely to have pleomorphic cells (23% vs. 49%; P = 0.042), and nearly always (95%) had areas with sheet-like growth (common pattern). To examine the reproducibility of these findings, we conducted blinded review of hematoxylin and eosin slides of 46 additional ALK-negative ALCLs using a 0 to 3 scoring system to predict likelihood of DUSP22 rearrangement, the results of which correlated strongly with subsequent findings by fluorescence in situ hybridization (P < 0.0001). Although all ALCLs share certain morphologic features, ALCLs with DUSP22 rearrangements show significant differences from other ALK-negative ALCLs, typically showing sheets of hallmark cells with doughnut cells and few large pleomorphic cells. These morphologic findings and our previous outcome data suggest that ALK-positive ALCLs and DUSP22-rearranged ALCLs represent prototypical ALCLs, whereas ALCLs lacking rearrangements of both DUSP22 and ALK require further study.

Nogales F F, Goyenaga P, Preda O, Nicolae A, Vieites B, Ruiz-Marcellan M C, Pedrosa A & Merino M J (2012) Histopathology 60, 748–757 An analysis of five clear cell papillary cystadenomas of mesosalpinx and broad ligament: four associated with von Hippel-Lindau disease and one aggressive sporadic type Aims: Clear cell papillary cystadenoma (CCPC) is associated with von Hippel-Lindau disease (VHLD), but rarely involves mesosalpinx and broad ligament (M/BL). This study provides new data about its behaviour and immunophenotype. Methods and results: We performed an analysis of four benign cases of CCPC of M/BL with either characteristic clinical features or genetic markers [loss of heterozygosity (LOH)] of VHLD in patients ranging from 24 to 36 years and a sporadic case in a 52-year-old presenting with peritoneal metastases. All CCPCs were papillary but had solid and tubular areas. Haemorrhage, thrombosis and scarring were constant features and related to an unusual pattern of sub-epithelial vascularity. All clear or oxyphilic cells co-expressed cytokeratin 7 (CK7), CAM5.2 and vimentin, with strong apical CD10 and nuclear paired box gene 2 (PAX2) immunoreactivity. Three cases also showed positivity for VHL40, epithelial membrane antigen (EMA), Wilms’ tumour suppressor gene (WT-1) and cancer antigen 125 (CA125) but only one expressed renal cell carcinoma (RCC) antigen. Vascular plexus overexpressed nuclear and cytoplasmic WT-1. Conclusion: The VHLD-associated cases appeared to be benign, but the sporadic case exhibited a low malignant potential. CCPCs show histological and immunophenotypical similarities with the recently reported clear cell papillary RCC, although the previously unreported apical CD10 and nuclear PAX2 expression may be related to their mesonephric origin. CCPC has a distinctive sub-epithelial vascular pattern that is consistent with its pathogenesis.

Primary central nervous system (CNS) lymphomas are relatively rare with the most common subtype being diffuse large B-cell lymphoma. Primary CNS T-cell lymphomas (PCNSTL) account for 1 mutation, and none showed overlapping mutations. These included mutations in DNMT3A, KRAS, JAK3, STAT3, STAT5B, GNB1, and TET2 genes, genes implicated previously in other T-cell neoplasms. The outcome was heterogenous; 2 patients are alive without disease, 4 are alive with disease, and 6 died of disease. In conclusion, PCNSTLs are histologically and genomically heterogenous with frequent phenotypic aberrancy and a cytotoxic phenotype in most cases.

We review the current knowledge on human yolk sactumours (YSTs) 50 years after their initial description.Their complex nomenclature and histogenesis stressthe fact that they are not a discrete entity, but representa multifaceted group of neoplasms, for which the termprimitive endodermal tumours would be more appropri-ate, accounting for their capacity to differentiate intovarious extraembryonal and somatic cell types. Differ-ent histological patterns of human YSTs correlate withthe developmental potential of primitive endoderm andmesenchyme, but they are also similar to some murineexperimental tumours. Exceptionally, YSTs replicatethe tubular structures of the human yolk sac andallantois. Endodermal somatic differentiation repro-duces pulmonary, intestinal and hepatic tissues andare identical with some, embryonal-type endodermal,gastric and lung carcinomas, which are indistinguish-able from YSTs. YSTs may show an overgrowth of theirmesenchymal (sarcomatous) and epithelial compo-nents (such as mucinous carcinoma or carcinoid) andalso be a source of haematological malignancies. YSTsassociated with non-germ cell tumours probably orig-inate from malignant pluripotent somatic stem cells.Only AFP and glypican-3 are characteristic immuno-histochemical markers. Pluripotent antibodies (SALL4,Lin28, IMP-3) help in differential diagnoses, whilesome differentiation markers (CDX2, TTF-1, HepPar1)facilitate recognition of unusual variants of YSTs.Keywords: AFP, glypican-3, human yolk sac, nomenclature, primitive endodermal tumours, yolk sac tumourAbbreviations: AFP, alpha-foetoprotein; HepPar1, hepatocyte paraffin 1; TTF-1, thyroid transcription factor 1;YST, yolk sac tumourYolk sac tumours (YSTs) are intriguing neoplasms;possibly few tumours have been known by moreambiguous names in recent history. The concepts thatled to their identification tell a fascinating story, oftenreminiscent of a detective tale with an abundance of redherrings, due to their occurrence in different sites, theirvaried histology and the interpretation of the relation-ships between experimental and human pathology.

A 55-year-old woman underwent radical mastectomy and axillary node dissection because of an invasive ductal carcinoma with neuroendocrine features. Histologically, all 22 sampled lymph nodes had widespread cystic inclusions lined by a regular, serous-type epithelium positive for cytokeratin-7, WT-1, CA125, and estrogen receptors. Papillary projections were found in the lumen of some cysts. The lesions were consistent with florid, papillary endosalpingiosis (FPE), a hitherto unreported condition in a supradiaphragmatic location. Metastases from papillary carcinomas of ovary, breast, or thyroid were excluded considering the lesion's immunophenotype (negative for mammaglobin and TTF-1) and the absence of both atypical features and a concurrent abdominal serous tumor. In only one node, lesions co-existed with a metastasis of breast carcinoma. Supradiaphragmatic FPE represents a pitfall in the differential diagnosis of metastases, especially in sentinel nodes, since it may increase their size and reveal an unusual ultrasonographic image. Clinicopathologic findings and a focused immunohistochemical study led to the correct diagnosis of this benign lesion.

We report the differential clinicopathologic and immunophenotypical features of 2 pure ovarian ependymomas of extra-axial type with a predominant microcystic, anaplastic pattern occurring in patients aged 22 and 32 years and a unique myxopapillary pigmented ependymoma that originated within an ovarian mature cystic teratoma in a 35-year-old woman. The latter had a central nervous system phenotype different from that previously reported in ovarian ependymomas of extra-axial types, being negative for estrogen and progesterone receptors, epithelial membrane antigen and cytokeratin 34βE12, cell adhesion molecule 5.2, and cytokeratin 7. Furthermore, its benign behavior contrasted with the aggressive course of the other 2 ependymomas of extra-axial types, in which peritoneal invasion was present at the time of diagnosis. These findings illustrate that both central and extra-axial types of ependymoma show phenotypic variations that may point to either a derivation from different precursors or differentiation along diverse pathways. Thus, whereas ependymomas of extra-axial types would represent neometaplastic phenomena, those originated from the nervous tissue of teratomas resemble central nervous system ependymomas. Moreover, the dissimilarities between central and peripheral types of ependymoma would parallel the phenotypic differences present in primitive neural tumors of the female genital tract.

We report an unusual case of primary scrotal extramammary Paget disease that infiltrated reticular dermis and lymph vessels, with metastasis in inguinal lymph node. The 67-year-old patient died at 14 months due to systemic metastases. The tumor, which was located in epidermis and infiltrated the dermis, comprised cells with wide, granular, and eosinophilic cytoplasm and intense positivity for antimitochondrial antibody. This seems to be the first report of oncocytic changes in extramammary Paget disease.

We present a unique case of bilateral gonadoblastoma in a 23-year-old patient with Swyer syndrome. The gonadoblastoma on both sides underwent synchronous neoplastic transformation, into a stage I germinoma in the right streak gonad and a highly differentiated Sertoli cell tumor in the left one. The latter was associated with a myriad of microscopic, Sertoli cell implants on the peritoneal surface, which were considered benign as they had a high grade of differentiation, minimal proliferative activity, and an absence of invasion. Most probably, the pathogenesis of this abdominal dissemination was iatrogenic, with implantation occurring mechanically as a result of the multiple laparoscopic biopsies performed on both of the streak gonads 2 months before the abdominal surgery. The pathogenesis of other benign abdominal implants is discussed.

SJL/J mice exhibit a high incidence of mature B-cell lymphomas that require CD4(+) T cells for their development. We found that their spleens and lymph nodes contained increased numbers of germinal centers and T follicular helper (TFH) cells. Microarray analyses revealed high levels of transcripts encoding IL-21 associated with high levels of serum IL-21. We developed IL-21 receptor (IL21R)-deficient Swiss Jim Lambart (SJL) mice to determine the role of IL-21 in disease. These mice had reduced numbers of TFH cells, lower serum levels of IL-21, and few germinal center B cells, and they did not develop B-cell tumors, suggesting IL-21-dependent B-cell lymphomagenesis. We also noted a series of features common to SJL disease and human angioimmunoblastic T-cell lymphoma (AITL), a malignancy of TFH cells. Gene expression analyses of AITL showed that essentially all cases expressed elevated levels of transcripts for IL21, IL21R, and a series of genes associated with TFH cell development and function. These results identify a mouse model with features of AITL and suggest that patients with the disease might benefit from therapeutic interventions that interrupt IL-21 signaling.

Mediastinal B-cell lymphomas present in the mediastinum and are most frequent in young patients. Nodular sclerosis Hodgkin lymphoma (NSHL) and primary mediastinal B-cell lymphoma (PMBL) are the common types, whereas mediastinal gray-zone lymphoma (MGZL) is extremely rare and has pathological features intermediate between NSHL and PMBL. The indeterminate pathobiology of MGZL has led to uncertainty regarding therapeutic strategy, and its clinical characteristics and treatment have not been characterized. We conducted a prospective study of infusional dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine, prednisone, and rituximab (DA-EPOCH-R) and filgrastim in untreated MGZL. We analyzed biomarkers of outcome and compared their clinical and biological characteristics to PMBL. Twenty-four MGZL patients had a median age of 33 years (range, 14 to 59 years), and 46% had mediastinal masses ≥10 cm. At 59 months median follow-up, the event-free survival and overall survival were 62% and 74%, respectively. The serum absolute lymphocyte count, the presence of tumor-infiltrating dendritic cells, CD15 expression on the malignant cells, and tumor morphology were biomarkers of outcome in MGZL. Compared with PMBL, MGZL patients were more likely to be male, express CD15, have lower expression of CD20, and have a worse outcome. DA-EPOCH-R alone is effective in MGZL. The trial was registered at ClinicalTrials.gov (NCT00001337).

Induced pluripotent stem cell (iPSC) therapies offer a promising path for patient-specific regenerative medicine. However, tumor formation from residual undifferentiated iPSC or transformation of iPSC or their derivatives is a risk. Inclusion of a suicide gene is one approach to risk mitigation. We introduced a dimerizable-“inducible caspase-9” (iCasp9) suicide gene into mouse iPSC (miPSC) and rhesus iPSC (RhiPSC) via a lentivirus, driving expression from either a cytomegalovirus (CMV), elongation factor-1 α (EF1α) or pluripotency-specific EOS-C(3+) promoter. Exposure of the iPSC to the synthetic chemical dimerizer, AP1903, in vitro induced effective apoptosis in EF1α-iCasp9-expressing (EF1α)-iPSC, with less effective killing of EOS-C(3+)-iPSC and CMV-iPSC, proportional to transgene expression in these cells. AP1903 treatment of EF1α-iCasp9 miPSC in vitro delayed or prevented teratomas. AP1903 administration following subcutaneous or intravenous delivery of EF1α-iPSC resulted in delayed teratoma progression but did not ablate tumors. EF1α-iCasp9 expression was downregulated during in vitro and in vivo differentiation due to DNA methylation at CpG islands within the promoter, and methylation, and thus decreased expression, could be reversed by 5-azacytidine treatment. The level and stability of suicide gene expression will be important for the development of suicide gene strategies in iPSC regenerative medicine.

Induced pluripotent stem cell (iPSC)-based cell therapies have a great potential for regenerative medicine, but are also potentially associated with tumorigenic risks. Current rodent models are not the optimal predictors of efficiency and safety for clinical application. Therefore, we developed a clinically relevant non-human primate model to assess the tumorigenic potential and in vivo efficacy of both undifferentiated and differentiated iPSCs in the autologous settings without immunosuppression. Undifferentiated autologous iPSCs indeed formed mature teratomas in a dose-dependent manner. However, tumor formation was accompanied by an inflammatory reaction. On the other hand, iPSC-derived mesodermal stromal-like cells formed new bone in vivo without any evidence of teratoma formation. We therefore show for the first time in a large animal model that closely resembles human physiology that undifferentiated autologous iPSCs form teratomas, and that iPSC-derived progenitor cells can give rise to a functional tissue in vivo.