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Background Opportunistic infections and malignancies such as malignant lymphoma and Kaposi sarcoma are significant complications of human immunodeficiency virus (HIV) infection. However, following the introduction of antiretroviral therapy in Japan in 1997, the incidence of clinical complications has decreased. In the present study, autopsy cases of HIV infection in Japan were retrospectively investigated to reveal the prevalence of opportunistic infections and malignancies. Methods A total of 225 autopsy cases of HIV infection identified at 4 Japanese hospitals from 1985–2012 were retrospectively reviewed. Clinical data were collected from patient medical records. Results Mean CD4 counts of patients were 77.0 cells/μL in patients who received any antiretroviral therapy during their lives (ART (+) patients) and 39.6 cells/μL in naïve patients (ART (−) patients). Cytomegalovirus infection (142 cases, 63.1%) and pneumocystis pneumonia (66 cases, 29.3%) were the most frequent opportunistic infections, and their prevalence was significantly lower in ART (+) patients than ART (−) patients. Non-Hodgkin lymphoma and Kaposi sarcoma were observed in 30.1% and 16.2% of ART (−) patients, and 37.9% and 15.2% of ART (+) patients, respectively. Malignant lymphoma was the most frequent cause of death, followed by cytomegalovirus infection regardless of ART. Non-acquired immunodeficiency syndrome (AIDS)-defining cancers such as liver and lung cancer caused death more frequently in ART (+) patients (9.1%) than in ART (−) patients (1.5%; P = 0.026). Conclusions The prevalence of infectious diseases and malignancies were revealed in autopsy cases of HIV infection in Japan. The prevalence of cytomegalovirus infection and pneumocystis pneumonia at autopsy were lower in ART (+) patients than ART (−) patients. Higher prevalence of non-AIDS defining malignancies among ART (+) patients than ART (−) patients suggests that onsets of various opportunistic infections and malignancies should be carefully monitored regardless of whether the patient is receiving ART.

The patient was a 72-year-old female with the chief complaint of abdominal fullness. A giant primary myoma of the uterine cervix was suspected, and total hysterectomy was performed. Based on a postoperative histopathological examination of the tumor a diagnosis of diffuse large B-cell lymphoma (DLBCL) was made in the uterus and a mass in the greater omentum was diagnosed as a marginal zone B-cell lymphoma (MZBCL). No flow-cytometry studies or chromosome or gene examinations were performed on a fresh specimen. The results of an examination of a paraffin block histopathology specimen by fluorescence in-situ hybridization (FISH) showed no mucosa associated lymphoid tissue lymphoma translocation gene 1 (MALT1) (18q21.1), B-cell lymphoma 2 (BCL2) (18q21.3), or BCL6 (3q27) split signals in either the uterus or the greater omentum, however, trisomy 18 was detected in approximately 50%-70% of the tumor cells in both the uterus and the greater omentum. Trisomy 18 was present in around 15-33% of the DLBCL cells and MZBCL cells. These findings suggested a strong possibility that the tumor cells in the uterus and greater omentum were the same clone and that transformation from MZBCL to DLBCL had occurred. Since DLBCLs that result from a transformation usually have a worse outcome than de novo DLBCLs, even when a DLBCL seems to have originated in the uterus the surrounding tissue should always be examined, and caution should be exercised in regard to transformation from a low-grade B-cell lymphoma to a DLBCL.

The introduction of combined antiretroviral therapy (ART) has reduced the mortality of patients with human immunodeficiency virus-1 infection worldwide. However, malignant lymphoma is a severe and frequent complication seen in patients with acquired immunodeficiency syndrome (AIDS). The diagnostic criteria for some categories of AIDS-related lymphoma were revised in the World Health Organization International Classification of Lymphoma, fourth edition. The purpose of this study was to assess the clinicopathological characteristics of Japanese patients with AIDS-related lymphoma according to the revised classification. In this retrospective study, 207 AIDS-related lymphoma cases diagnosed between 1987 and 2012 in Japan were subjected to histological subtyping and clinicopathological analyses. Diffuse large B-cell lymphoma (DLBCL) was the predominant histological subtype throughout the study period (n = 104, 50%). Among the DLBCL cases, 24% were of the germinal center (GC) type and 76% were of the non-GC type. Non-GC-type cases showed a significantly lower 1-year survival rate (43%) than the GC-type cases (82%). Cases of Burkitt lymphoma (n = 57, 28%), plasmablastic lymphoma (n = 16, 8%), primary effusion lymphoma (n = 9, 4%), Hodgkin lymphoma (n = 8, 4%), and large B-cell lymphoma arising in Kaposi sarcoma-associated herpesvirus-associated multicentric Castleman disease (n = 2, 1%) were also observed. Hodgkin lymphoma was more common in patients receiving ART (11.1%) than in ART-naive patients (1.4%). Statistical analyses identified CD10 negativity, BCL-6 negativity, Epstein–Barr virus positivity, and Kaposi sarcoma-associated herpesvirus positivity as risk factors for poor prognosis. This information will help in the early diagnosis of lymphoma in patients with AIDS.

An 85-year-old man presented with pain and numbness in the left buttock, and physical examination revealed an approximately 7 cm mass extending from the first to the third sacral vertebrae; biopsy of the mass led to the diagnosis of CD10-negative, BCL6-weakly positive, MUM1-positive, non-germinal center (non-GC) type diffuse large B-cell lymphoma (DLBCL). Furthermore, serological testing showed negative results for Epstein-Barr virus (EBV) infection, and fluorescence in situ hybridization (FISH) revealed a MYC translocation. Radiographs showed no remarkable osteolytic bone destruction, and the patient was staged with Stage IAE. After 8 cycles of rituximab therapy and 6 cycles of CHOP therapy, complete remission has been maintained until now, approximately 1 year after the treatment. Primary sacral lymphoma is very rare, with only 6 reported cases, including the present one. A review of the reported cases revealed that the disease predominantly affects elderly men, is usually non-GC-type DLBCL and stage IAE, measures approximately 2-7 cm in diameter in general, and does not show early recurrence after chemotherapy or chemoradiotherapy. There is no report in the literature yet of primary sacral DLBCL with MYC translocation, and this is the first case report. On the other hand, 35 cases of CD10-negative DLBCL with MYC translocation, including the present one, have been reported, and a review of the reported cases showed that the disease predominantly affects Asians, middle-aged or elderly men, shows positivity for either BCL6 or MUM1 and negativity for EBV, and has a high international prognostic index and poor prognosis.

Multiple Lymphomatous Polyposis (MLP) is characterized by multiple polyps with lymphoma invasion involving long segments of the Gastrointestinal (GI) tract. Most MLP are thought to represent Mantle Cell Lymphoma (MCL) of the GI tract. However, some follicular lymphomas, mucosa-associated lymphoid tissue lymphomas, and adult T-cell lymphomas [5] have been found to show a multiple polypoid appearance throughout long segments of the GI tract. We report a case with MLP associated with Small Lymphocytic Lymphoma (SLL). SLL in extranodal sites is difficult to diagnose and the clinical course is different from that of MCL. MCL has a more aggressive clinical course than Chronic Lymphocytic Leukemia or SLL (CLL/SLL). A median survival time of CLL/SLL is 7 to 10 years, while patients with MCL have a median survival of 3 years .

Introduction Generation of engraftable hematopoietic stem cells (HSCs) from pluripotent stem cells (PSCs) has long been thought an ultimate goal in the field of hematology. Numerous in vitro differentiation protocols, including trans-differentiation and forward programming approaches, have been reported but have so far failed to generate fully functional HSCs. We have previously demonstrated proof-of-concept for the in vivo generation of fully functional HSCs from induced PSCs (iPSCs) through teratoma formation (Suzuki et al., 2013). However, this method is time-consuming (taking over two months), HSCs are generated at low frequencies, and additionally require co-injection on OP9 stromal cells and SCF/TPO cytokines. Here, we present optimization of in vivo HSC generation via teratoma formation for faster, higher-efficiency HSC generation and without co-injection of stromal cells or cytokines. Results First, we screened reported in vitro trans-differentiation and forward programming strategies for their ability to generate HSCs in vivo within the teratoma assay. We tested iPSCs transduced with the following dox-inducible TF overexpression vectors: (1) Gfi1b, cFOS and Gata2 (GFG), which induce hemogenic endothelial-like cells from fibroblast (Pereira et al.,2013); (2) Erg, HoxA9 and Rora (EAR), which induce short-term hematopoietic stem/progenitor cell (HSPC) formation during embryoid body differentiation (Doulatov et,al., 2013); and (3) Foxc1, which is highly expressed the CAR cells, a critical cell type for HSC maintenance (Oomatsu et al.,2014). We injected iPSCs into recipient mice, without co-injection of stromal cells or cytokines, and induced TF expression after teratoma formation by dox administration. After four weeks, GFG-derived teratomas contained large numbers of endothelial-like and epithelial-like cells, and importantly GFG-derived hematopoietic cells could also be detected. EAR-teratomas also generated hematopoietic cells, although at lower frequencies. By contrast, hematopoietic cells were not detected in control teratomas or Foxc1-teratomas. Through use of iPSCs generated from Runx1-EGFP mice (Ng et al. 2010), and CUBIC 3D imaging technology (Susaki et al. 2014), we were further able to demonstrate that GFG-derived hematopoietic cells were generated through a haemogenic endothelium precursor. Next, we assessed whether HSPC-deficient recipient mice would allow greater expansion of teratoma-derived HSCs. This was achieved by inducing c-kit deletion within the hematopoietic compartment of recipient mice (Kimura et al., 2011) and resulted in a ten-fold increase in the peripheral blood frequency of iPSC-derived hematopoietic cells. We further confirmed similar increases in iPSC-derived bone marrow cells, and in vivo HSC expansion, through bone marrow transplantation assays. Finally, we have been able to shorten the HSC generation time in this assay by five weeks through use of transplantable teratomas, rather than iPSCs. Conclusions We have demonstrated that GFG-iPSCs induce HSC generation within teratomas, via a hemogenic endothelium precursor, and that use of HSPC-deficient recipient mice further promotes expansion of teratoma-derived HSCs. These modifications now allow us to generate engraftable HSCs without co-injection of stromal cells or cytokines. Additionally, use of transplantable teratomas reduced HSC generation times as compared with the conventional assay. These findings suggest that our in vivo system provides a promising strategy to generate engraftable HSCs from iPSCs. Disclosures No relevant conflicts of interest to declare.

The incidence of Hodgkin lymphoma (HL) is paradoxically increasing in the combination anti-retroviral therapy (cART) era. However, there has been no nationwide survey of human immunodeficiency virus (HIV)-associated HL (HIV-HL) in Japan. We retrospectively examined the clinical characteristics and outcomes of 19 newly diagnosed HIV-HL patients at 11 HIV/AIDS and hematology regional hospitals in Japan between 1991 and 2010. At the time of HL diagnosis, 79 % of patients were receiving cART. All the patients, but one received HL diagnoses in the cART era. The median CD4+ cell count at HIV-HL diagnosis was 169/μl. Mixed-cellularity classical Hodgkin lymphoma was the most common subtype occurring in 68 % of the patients; 89 % of the patients were positive for Epstein–Barr virus. Of these 19 patients, 84 % were in advanced stages, with bone marrow involvement observed in 47 % of the patients; 58 % had extranodal sites. All the treated patients were given cART concurrent with HL therapy. The complete remission rate of the treated patients was 87 %. The median OS of the entire cohort was 17 months. These results suggest that the characteristics of HIV-HL in Japan are more aggressive than those of non-HIV-associated HL in Japan, but standard chemotherapy is effective and feasible.

ALK-positive large B-cell lymphoma is a rare subtype of lymphoma, and most cases follow an aggressive clinical course with a poor prognosis. We examined an ALK-positive large B-cell lymphoma case showing an anti-ALK immunohistochemistry pattern distinct from those of 2 known ALK fusions, CLTC-ALK and NPM-ALK, for the presence of a novel ALK fusion; this led to the identification of SQSTM1-ALK. SQSTM1 is an ubiquitin binding protein that is associated with oxidative stress, cell signaling, and autophagy. We showed transforming activities of SQSTM1-ALK with a focus formation assay and an in vivo tumorigenicity assay using 3T3 fibroblasts infected with a recombinant retrovirus encoding SQSTM1-ALK. ALK-inhibitor therapies are promising for treating ALK-positive large B-cell lymphoma, especially for refractory cases. SQSTM1-ALK may be a rare fusion, but our data provide novel biological insights and serve as a key for the accurate diagnosis of this rare lymphoma.

A 53-year-old woman was referred to our hospital for further examination of a rectal polypoid lesion. Colonoscopy revealed a submucosal tumor in the rectum (Ra) and a diagnosis of MALT lymphoma was made on the histological examination of the biopsy specimens and Southern blot analysis of the immunoglobulin heavy chain gene rearrangement. Although the patient was negative for Helicobacter pylori, H. pylori eradication therapy was performed. Colonoscopy 3 months after the eradication therapy showed disappearance of the rectal tumor. H. pylori eradication appears to be a useful treatment for not only H. pylori-positive colonic MALT lymphoma but H. pylori-negative colonic MALT lymphoma.

Although allogeneic hematopoietic stem cell transplantation has recently been applied to patients with myelofibrosis with reproducible engraftment and resolution of marrow fibrosis, no data describe the outcomes of umbilical cord blood transplantation. We describe 14 patients with primary (n = 1) and secondary myelofibrosis (n = 13) who underwent reduced-intensity umbilical cord blood transplantation. Conditioning regimens included fludarabine and graft-versus-host disease prophylaxis composed cyclosporine/tacrolimus alone (n = 6) or a combination of tacrolimus and mycophenolate mofetil (n = 8). Thirteen patients achieved neutrophil engraftment at a median of 23 days. The cumulative incidence of neutrophil and platelet engraftment was 92.9% at day 60 and 42.9% at day 100, respectively. Posttransplantation chimerism analysis showed full donor type in all patients at a median of 14 days. The use of umbilical cord blood could be feasible even for patients with severe marrow fibrosis, from the viewpoint of donor cell engraftment.

Signaling through the Notch1 receptor has a pivotal role in early thymocyte development. Gain of Notch1 function results in the development of T-cell acute lymphoblastic leukemia in a number of mouse experimental models, and activating Notch1 mutations deregulate Notch1 signaling in the majority of human T-cell acute lymphoblastic leukemias. Notch2, another member of the Notch gene family, is preferentially expressed in mature B cells and is essential for marginal zone B-cell generation. Here, we report that 5 of 63 (approximately 8%) diffuse large B-cell lymphomas, a subtype of mature B-cell lymphomas, have Notch2 mutations. These mutations lead to partial or complete deletion of the proline-, glutamic acid-, serine- and threonine-rich (PEST) domain, or a single amino acid substitution at the C-terminus of Notch2 protein. Furthermore, high-density oligonucleotide microarray analysis revealed that some diffuse large B-cell lymphoma cases also have increased copies of the mutated Notch2 allele. In the Notch activation-sensitive luciferase reporter assay in vitro, mutant Notch2 receptors show increased activity compared with wild-type Notch2. These findings implicate Notch2 gain-of-function mutations in the pathogenesis of a subset of B-cell lymphomas, and suggest broader roles for Notch gene mutations in human cancers.

Recent genetic studies have revealed frequent and specific pathway mutations involving multiple components of the RNA splicing machinery in myelodysplasia. Among these, SRSF2 mutations are more prevalent in CMML subtype and are associated with poor prognosis. Mutations showed a prominent hotspot involving proline 95, causing either P95H, P95L, or P95 conversion. Comprehensive analysis in our large cohort of MDS revealed that SRSF2 mutations showed a significant trend to coexist with TET2, STAG2, ASXL1 and RUNX1 mutations, while being mutually exclusive with EZH2 mutations. On the other hand, the molecular mechanism by which SRSF2 mutations lead to myelodysplasia remains largely unknown. To elucidate the role of SRSF2 mutations in the development of myelodysplasia, we generated a heterozygous conditional knock-in mouse model of Srsf2 P95H mutation and crossed them with Vav1-Cre transgenic mice. Srsf2 P95H mutant mice exhibited macrocytic anemia, otherwise no significant changes in total peripheral blood (PB) cell counts compared to wild-type mice at 8-15 weeks after birth. There was no significant difference in lineage composition as well as blood cell morphology between wild-type and mutant mice in both bone marrow (BM) and PB. Flow cytometry of BM cells showed significant decrease of the number of hematopoietic stem cells (HSCs) and multipotent progenitor cells defined as Lin-Sca-1+Kit+ (LSK) fractions in Srsf2 P95H mice compared to wild-type mice. On the other hand, there were no significant differences in the number of more differentiated progenitor cells including common myeloid progenitors (CMPs), granulocyte/macrophage lineage-restricted progenitors (GMPs), megakaryocyte/erythrocyte lineage-restricted progenitors (MEPs), and common lymphoid progenitors (CLPs) between Srsf2 P95H and wild-type mice. These observations suggested that heterozygous Srsf2 mutation led to deregulation of hematopoietic stem cells, which however, is not sufficient for the development of MDS. We next performed noncompetitive transplantation experiments to assess the cell intrinsic effects of Srsf2 P95H mutations. In PB, decreased white blood cell counts and progressive anemia were observed in mutant mice, which were evident as early as one month after transplantation. Cytological analysis of PB revealed morphological abnormalities in mice reconstituted with Srsf2 mutated cells, including hypersegmentation in neutrophils and dysplasia in the erythroid lineage. Srsf2 mutant-reconstituted mice showed normo-to-hypercellular marrow, where abnormal megakaryocyte distribution adjacent to trabecular bone and erythroid dysplasia was observed. Flow cytometrical analysis revealed decreased numbers of HSCs, LSK fractions and CMPs, whereas there was no significant change in the number of MEPs, GMPs and CLPs in BM. The BM erythroid progenitors were decreased in mutant-reconstituted mice, whereas the mutant mice showed splenic erythropoiesis with increased erythroid progenitors, suggesting the presence of extramedullary hematopoiesis, which was not seen in wild-type Srsf2 transduced mice. These observations suggested that the Srsf2 mutation led to ineffective hematopoiesis and morphological abnormalities, which seemed to recapitulate the phenotype of MDS. Subsequently, we assessed the reconstitution capacity of whole BM cells from Srsf2 mutant mice in competitive transplantation experiments. The donor chimerism of Srsf2 P95H-derived cells in PB was significantly lower than that of wild-type cells. At 4 months post transplantation, the chimerism of Srsf2 P95H-derived cells was remarkably lower than that of wild-type cells in the fractions of HSCs, MPPs, CMPs, MEPs, GMPs and CLPs in BM. Furthermore, the reduced donor chimerism for Srsf2 P95H mutants was recapitulated in secondary transplantation experiments. In summary, our results demonstrated that heterozygous P95H mutation of Srsf2 led to deregulation of hematopoietic stem cells that was evident from reduced competitive repopulation and impaired hematopoietic differentiation. Whereas mice reconstituted with Srsf2 mutant BM cells developed MDS-like phenotype in non-competitive transplantation setting, Srsf2 mutation by itself does not seem to be sufficient to develop MDS without transplantation, raising the possibility that an additional genetic and/or epigenetic events was required for overt MDS phenotype. Disclosures No relevant conflicts of interest to declare.

B-cell receptor (BCR) signaling is a major source of gene expression signature important for B cell survival, functions, and development. The integrated signaling amplitude should be equilibrated; when chronically activated by genetic perturbations or other mechanisms, BCR signaling has been accepted as a stem in the pathogenesis of malignant lymphoma/leukemia. The promiscuous signaling network without appropriate alleviation is an essential property of cancers. Diffuse large B-cell lymphoma (DLBCL) with aggressive phenotypes often associates with BCR signaling activation and epigenetic abnormalities, both of which are well correlated with lymphoma subtypes and disease progression. However, the relationship of the two fundamental characteristics is unknown. It is also still unclear the mechanism by which the expression of functionally important genes is continuously deregulated. microRNAs (miRNAs) are an emerging class of intrinsic buffering molecules that have diverse functions in mainly post-transcriptional regulation through miRNA-RISC (miRISC) formation. Using optimized RISC-capture assay, we revealed that multiple BCR signaling factors were persistently regulated by miRNA in human B cells. Clinical samples from newly diagnosed patients with DLBCL (n=83) showed epigenetic loss of an essential miRNA set (miR-200c, miR-203, miR-31). Conventional screening and RISC profiling identified multiple targets (CD79B, SYK, PKCbII, PLCg1, IKKb, NIK, MYD88, PI3K class I (a/b/d/g), RasGRP3); the miRNA-orchestrated overlapping interactome suggested multiple regulatory windows in signaling pathways, which implied their compensatory roles. The shared components within the interconnected signaling pathways were under constant surveillance by the miRNAs. We demonstrated that simultaneous depletion of the key miRNAs enhanced translation of the multiple targets and caused seamless signaling crosstalk among canonical/noncanonical NF-kB pathways, PI3K-Akt-mTOR and Ras-Erk cascades, and downstream of BCR and BAFF receptors. In addition to the miRNA loss, mTOR activation was also positively correlated with signaling amplitude, offering the possibility of selective therapy targeting the translation machinery. The defenseless signaling crosstalk appeared to be a prerequisite for lymphoma development because the essential miRNA set were functionally lost in all tested lymphoma samples. Surprisingly, a common epigenetic mechanism was identified. Polycomb-mediated H3K27me3 accumulation and reciprocal H3K4me3 loss were frequently observed at the miRNAs loci in primary DLBCL samples. We found that lymphoma-associated deregulation (mutation and/or expression change) of EZH2 and MLL2 cooperated to cause the sustained signaling activities of NF-kB, Ras-Erk, PI3K-Akt and mTOR pathways through miRNA silencing en masse. Of note, the perturbation of histone-modifying polycomb and trithorax groups resulted from variations of pooled miRNAs and signaling integrity. The identified coherent circuit may be a source of pathological robustness and phenotypic convergence. Most malignant B cell clones have some kind of genetic lesions. In particular, recurrent variations have been identified within signaling cascades, where miRNA-formed cooperative gene interference (CGI) could buffer the signaling noise. We re-established some experimental models that mimicked the signaling cascade observed in clinically established malignant clones. We experimentally confirmed the buffering roles of the key miRNAs against genetic mutation/alteration of CARD11, A20, MYD88 and PTEN. Reciprocally, coordinated reduction of the functional miRNAs promoted biological processes caused by genetic perturbations. It is therefore conceivable that systematic redundancy of miRNA is inherently required for robustness against genetic alterations that are acquired in lymphoma evolution. We illustrate an example of a biological masterplan comprised of signaling pathways, compensatory actions of multi-layered miRNAs, translation regulation and epigenetic mechanisms. Malignant cell opts for epigenetic reprogramming to stabilize mutation-driven processes and to surmount the demarcation threshold of transformation. Reversing the plastic characteristics of epigenetic alterations is expected in future clinical settings. Disclosures Yamagishi: Daiichi Sankyo Co., Ltd.: Research Funding. Watanabe:Daiichi Sankyo Co., Ltd.: Research Funding.

Primary adrenal lymphoproliferative disorder (LPD) is an extremely rare disease that is widely known to be associated with methotrexate (MTX) use in patients with rheumatoid arthritis (RA). A 70-year-old man was incidentally found to have a tumor at the dorsal part of the liver in a medical check-up. He had a history of RA treated with MTX. Abdominal ultrasonography demonstrated a low echoic mass (30 mm in diameter) at the dorsal part of the liver, located close to the inferior vena cava. Preoperative differential diagnoses included intrahepatic cholangiocarcinoma, adrenal tumor, and hepatic malignant lymphoma, but no definitive diagnosis was reached. On exploratory laparotomy, the tumor seemed to be derived from the right adrenal gland and adhered tightly to segment 7 of the liver. Therefore, right adrenectomy with partial resection of segment 7 of the liver was performed. Pathological findings revealed diffuse inflammatory cell infiltration with a population of small atypical lymphoid cells, with positive immunohistochemical evidence for Epstein–Barr virus (EBV). Final diagnosis was primary adrenal iatrogenic EBV-positive LPD, classified as “other iatrogenic immunodeficiency-associated LPDs: Hodgkin-like lesions.” In this report, we described the possibility of the spontaneous healing of MTX-associated LPD (MTX-LPD) before treatment and the importance of doubting MTX-LPD and doing immunostaining to necrotic tissue. To our knowledge, this is the first reported case of MTX-related EBV-positive LPD, Hodgkin-like lesion, of the unilateral adrenal gland in patient with RA.

Background and aims Spontaneous gastric perforation in the absence of chemotherapy is extremely rare. The authors encountered a case of spontaneous perforation of primary gastric lymphoma. Case presentation A 58-year-old man visited the authors’ hospital with acute severe epigastralgia. A large amount of free gas and a fluid collection around the stomach were noted on an abdominal computed tomography scan. The results of imaging studies indicated a perforated gastric ulcer, and a distal gastrectomy was performed. There was a large perforation about 50 mm in diameter in the anterior wall of the middle part of the stomach body. Microscopically, the full thickness of the gastric wall was diffusely infiltrated by a population of large atypical lymphoid cells. The lymphoid nature of these cells was indicated by the strongly positive immunohistochemical staining for CD20 and CD10. This confirmed the diagnosis of a germinal center B-cell-like type of diffuse large B cell lymphoma. Rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone were administered after the operation. Results and conclusion Gastrectomy should be considered if a giant ulcer with necrotic matter on the ulcer floor is seen on upper gastrointestinal endoscopy because of the possibility of gastric perforation. If upper gastrointestinal endoscopy shows a finding similar to the abovementioned one during chemotherapy, dose reduction of chemotherapy or gastrectomy should be considered.

[Background] Body cavity-based lymphoma (BCBL) arises in body cavity effusion without mass formation. Although there have been several case reports on HHV8-negative BCBL and the term "primary effusion lymphoma (PEL)-like lymphoma" has been coined, it is very rare and not defined in the current lymphoma classification. In those reports, HHV8-negative BCBL usually expresses B-cell markers and the prognosis seems to be better than those with HHV8-positive PEL with a few reports describing spontaneous regression of effusion. However, its clinicopathological features and prognosis remain unclear due to lack of retrospective study with sufficient number. [Method] We collected data of BCBL diagnosed between 1990 and 2014 from 42 institutions in Japan and clinicopathological features were retrospectively analyzed. We focused on clinicopathological features and prognosis of HHV8-negative BCBL, which was defined as HHV8-negative lymphoma that developed in body cavity effusion (pleural effusion, pericardial effusion, and ascites) without mass formation or extra-cavitary lesions at diagnosis. HHV8 status was assessed with immunohistochemical staining with anti-LANA-1 antibody (n=34) and/or polymerase chain reaction for HHV8 (n=31) of body-cavity effusion sample.Overall survival (OS), progression free survival (PFS), and time to progression (TTP) were calculated using Kaplan-Meier method. In patients without any systemic treatment for 3 months from diagnosis, failure of the first systemic treatment was considered as an event for PFS or TTP. [Results] Case report form of 71 patients with BCBL was collected. With central review, 4 patients did not meet the criteria of BCBL (existence of tumor mass or no objective evidence of lymphoma by morphology or immunophenotype) and 67 patients with BCBL were identified. Out of them, 50 and 6 were compatible with the diagnosis of HHV8-negative BCBL and PEL, respectively. In another 11 cases, HHV8 status could not be evaluated. In the 50 patients with HHV8-negative BCBL, male to female ratio was 1.3 : 1, and median age at the diagnosis was 76 years (57-98), HIV was negative in all of the 46 patients who were tested. Twenty-four patients (47%) had an underlying medical condition leading to fluid overload such as cirrhosis, cardiac disease, and renal dysfunction. Involved sites were pleural effusion (76%) followed by pericardial effusion (60%), and ascites (12%). Multiple sites were involved in 21 cases. The other clinical characteristics at the time of diagnosis were as follows: ECOG PS 0-1 (50%); B symptoms (14%); and elevated LDH (68%). Tumor cells expressed CD10 in 11/45 and CD20 in 48/50. Immunoglobulin light chain restriction was detected in 28/34. EBER in situ hybridization was positive in 4/32 (13%). The most common first-line systemic therapy was CHOP or CHOP-like with or without rituximab (n=38) followed by rituximab alone (n=2), rituximab with etoposide (n=2), and hyperCVAD/MA (n=1). One patient died within a month before initiating treatment, and five more patients had no systemic treatment at diagnosis for reasons such as comorbidity or frailty. Of the 43 patients treated with systemic therapy, the overall response rate was 98% with 70% achieving a complete remission. With a median follow up of 22 (0-147) months, 2-year OS, PFS, TTP of HHV8-negative BCBL was 83.6%, 76.8%, and 90.5%, respectively (Figure 1-3). Fifteen patients relapsed after achieving response: the same body-cavity effusion alone (n=7), different body-cavity effusion with or without the same site (n=2), intra- or extra-cavitary tumor mass formation (n=6). Eleven patients died and the causes of death were lymphoma (n=8) and others (n=3). Of the 5 patients without systemic treatment at diagnosis, systemic treatment was initiated in only 1 patient at 30 months due to re-emergence of effusion. The remaining 4 patients had had no systemic treatment for a median of 24 (5-147) months and 3 patients were alive without disease without any systemic therapy at last follow-up. [Conclusion] To the best of our knowledge, this is the largest retrospective study on HHV8-negative BCBL. HHV8-negative BCBL had distinct clinicopathological features from PEL. It affected HIV-negative elderly and the lymphoma cell was positive for B cell markers in most cases. Almost all of the patients responded to systemic treatment and its prognosis was favorable. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures No relevant conflicts of interest to declare.

Angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) are subtypes of T-cell lymphoma. Due to low tumor cell content and substantial reactive cell infiltration, these lymphomas are sometimes mistaken for other types of lymphomas or even non-neoplastic diseases. In addition, a significant proportion of PTCL-NOS cases reportedly exhibit features of AITL (AITL-like PTCL-NOS). Thus disagreement is common in distinguishing between AITL and PTCL-NOS. Using whole-exome and subsequent targeted sequencing, we recently identified G17V RHOA mutations in 60-70% of AITL and AITL-like PTCL-NOS cases but not in other hematologic cancers, including other T-cell malignancies. Here, we establish a sensitive detection method for the G17V RHOA mutation using a quantitative allele-specific polymerase chain reaction (qAS-PCR) assay. Mutated allele frequencies deduced from this approach were highly correlated with those determined by deep sequencing. This method could serve as a novel diagnostic tool for 60-70% of AITL and AITL-like PTCL-NOS.

Backgrounds Angioimmunoblastic T-cell lymphoma (AITL) is a distinct subtype of T-cell lymphoma, characterized by generalized lymphadenopathy and frequent autoimmune-like manifestations. The diagnosis of AITL is sometimes challenging for hematopathologists, because the tumor cell content is generally low and relatively large reactive lymphocytes are confused as tumor cells. Possibly because of the low tumor cell frequency, clonal rearrangement of T-cell receptor gene is undetectable in 30% of the cases. We identified recurrent mutations in RHOA at c.G50T, predicting to generate p.G17V in 70% of AITL and PTCL-NOS harboring AITL features, which implies diagnostic properties for AITL (M S-Y and SC, unpublished). Purpose To establish a novel cost-effective method to diagnose AITL, we performed allele-specific realtime PCR to detect RHOA G17V mutation. Methods Genomic DNA was extracted from 119 AITL and PTCL-NOS samples, which include 47 periodate-lysine-paraformaldehyde (PLP)-fixed, 12 formalin-fixed-paraffin- embedded (FFPE) and 60 frozen tissues. Forty-one out of 60 genomic DNA samples, purified from frozen tissue, were amplified by RepliG kit (QIAGEN). Allele-specific primers for RHOA G17V mutant and wild-type sequences were designed by Wangkumhang's algorithm. The [mut] and [WT] values were individually measured by realtime PCR using each primer set, and the [mut]/([mut]+[WT]) values were calculated. Mutant allele frequencies were determined by amplicon-based deep sequencing using MiSeq. Results The [mut] values were distributed from 1.5×10-7 to 7.6×10-2, and the [WT] values were from 7.9×10-5 to 1.3×10-2. The [mut]/[mut]+[WT] values were distributed from 1.9×10-4 to 8.5×10-1. We set a cut-off value to determine existence of mutation as 2% for MiSeq, and 1.3×10-2 for the [mut]/([mut]+[WT]) value. Then we compared these two methods to detect RHOA G17V mutation. Forty-three cases were positive for the RHOA mutation in this study cohort by MiSeq, including 32 AITL and 11 PTCL-NOS cases. The [mut]/([mut]+[WT]) values of DNA from FFPE samples tend to be lower than those from other samples, and 4 out of 12 FFPE samples determined as mutation-positive by MiSeq were not detected by our allele-specific realtime PCR. We therefore excluded the FFPE samples and analyzed the data of 107 DNA samples, purified from PLP-fixed and frozen tissues. Rank correlation coefficient was 0.753. Sensitivity was 97.4%, and specificity was 97.1%. Positive concordance rate was 94.9%, and negative concordance rate was 98.6%. Conclusions We established a method to detect RHOA G17V hotspot mutation for AITL. It is expected to be highly accurate and cost effective. Disclosures: No relevant conflicts of interest to declare.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) using cord blood or haploidentical donor is a promising alternative option for patients who can not find an HLA-matched donor. However, HLA-mismatch allo-HSCT may be complicated by graft-versus-host disease (GVHD), a major cause of non-relapse mortality mediated by alloreactive T cells. Infusion of anti-thymocyte globulin (ATG) is used both as a treatment for and as a prophylactic against GVHD but ATG, like other immunosuppressive regimens, reacts against cells without distinguishing between donor and recipient cells. ATG is polyclonal and causes many side effects such as allergic reaction and increasing susceptibility to infection due to repression of T cells. Our ultimate goal is to develop a novel therapeutic approach to GVHD with anti-HLA monoclonal antibody specifically targeting the mismatched HLA molecule of donor origin to transiently ablate alloreactive T cells. To generate allele-specific anti-HLA antibody (ASHmAb), we established a rapid and efficient strategy using two different HLA-transgenic mouse strains, HLA-A24 and HLA-A2 and immunized them with HLA-A* 02:01 and HLA-A* 24:02 tetramers loaded with cytomegalovirus PP65 peptide, respectively. Antibodies were screened for HLA allele-specific complement-dependent cytotoxicity in vitro. We successfully established three killing ASHmAbs (kASHmAbs) against HLA-A* 02:01, -A* 02:01/–A* 03:01, and -A* 23:01/-A* 24:02. In vivo cytotoxicity and specificity of a kASHmAb against HLA-A* 02:01 (A* 02:01-kASHmAb) was examined in detail using a xenogeneic GVHD mouse model. To induce fatal GVHD, non-irradiated NOD/Shi-scid/IL-2Rγnull (NOG) mice were injected with either HLA-A2 or HLA-A26 positive human peripheral blood mononuclear cells (PBMCs) from healthy donors (i.e. HLA-A2 mice or HLA-A26 mice, respectively). Administration of A* 02:01-kASHmAb promoted the survival of HLA-A2 mice to 100%, with a mean survival of more than 6 months. In contrast, administration of A* 02:01-kASHmAb to nonreactive HLA was not effective; all HLA-A26 mice died within 2 months (p Next, we examined the cytotoxicity of the kASHmAb on the human graft in bone marrow using humanized NOG mice. Sublethally irradiated NOG mice were reconstituted with CD34 positive hematopoietic stem/progenitor cells from HLA-A2 positive cord blood. These humanized mice showed about 70-90% human T, B and myeloid cells in the peripheral blood. When these mice were administrated with A* 02:01-kASHmAb for five consecutive days (60 mg/day), mature human blood cells disappeared immediately from the mouse peripheral blood. Interestingly, human PBMCs were detectable again in the mouse blood in 2-4 weeks after the last kASHmAb administration, suggesting kASHmAb may have preferential cytotoxic effect on mature PBMCs sparing hematopoietic stem progenitor cells. The mechanism of this preferential killing is not clear, but an optimal dose of kASHmAb may be safely administered to GVHD patients without permanently ablating the graft and necessitating repeated transplantation. This study is the first reported instance of using the cytotoxic effect of HLA antibodies against GVHD. Unlike ATG, kASHmAb specifically killed donor cells and contributed to the survival of the recipients. While this novel therapeutic approach requires a panel of kASHmAbs to different HLA alleles, this may open a new door for treatment of severe GVHD. Furthermore, optimization of the kASHmAb administration protocol may contribute to tolerance induction. Disclosures: No relevant conflicts of interest to declare.

Background EBV-associated post-transplant lymphoproliferative disorder (EBV-PTLD) is uncommon but one of serious complications after allogeneic stem cell transplantation (SCT). However, there has been little literature published on clinicopathological feature of it. Method We retrospectively investigated 825 cases of allogeneic SCT (unrelated bone marrow (uBM) 159, related peripheral blood (rPB) 94, cord blood (CB) 572) at Toranomon Hospital between January 2006 to November 2012. EBV-PTLD was defined as histologically confirmed Epstein-Barr virus (EBV) positive lymphoproliferative disorder developed after allogeneic SCT. Results We identified 12 cases of EBV-PTLD in our cohort. Cumulative incidence of EBV-PTLD at 2 years was 1.5%. Median time from allogeneic SCT to the diagnosis of EBV-PTLD was 6.4 (2.5-26) months. Eight patients were male and median age at the diagnosis of EBV-PTLD was 58.5 years (28-66). Underlying diseases were acute myeloid leukemia (n=5), myelodysplastic syndrome (1), acute lymphoblastic leukemia (2), adult T cell leukemia-lymphoma (1), aplastic anemia (2) and chronic myeloid leukemia in blastic phase (1). Conditioning regimens were fludarabine-based (n=10) and TBI/CY (n=2). None had an antithymocyte globulin-containing regimen. Donor sources were uBM (n=1) and CB (11). EBV serology before allogeneic SCT was tested in 11 and all were positive. Patients who received CB showed higher incidence of EBV-PTLD compared to those in non-CB cohort (2.2% vs 0.6%, p < 0.01), although patients characteristics was different between them. One patient developed PTLD after third allogeneic SCT. All but one patients had a history of acute graft-versus-host disease (aGVHD) of grade I (n=2), grade II (6) and grade III (3), respectively. Chronic GVHD was observed in 6 patients. Eight patients were on immunosuppressive therapy (IST) with calcineurin inhibitors and/or steroids when EBV-PTLD was suspected for the first time. Although lymphadenopathy was detected by CT scan in 7 patients, surface lymph nodes were swollen in only 3 patients. Initial manifestations were fever in 8, and diarrhea in 5 patients. EBV-PTLD was diagnosed from lymph nodes (n=3), skin (3), bone marrow (2), stomach/duodenum (1), colon (2), and lung (1), respectively. Histological feature was monomorphic (n=4), polymorphic (2), early lesion (4), and unknown (2), respectively. LMP1 and EBNA2 was positive in 40% (4/10) and 30% (3/10), suggesting latency status of I in 50% (6/12), II in 8.3% (1/12), III in 25% (3/12), and unknown in 16.7% (2/12). EBV DNA of 100 copies/microL or above was detected in peripheral blood in all of the EBV-PTLD cases. The treatment for EBV-PTLD were rituximab alone (n=3), rituximab plus reduction of IST (6), rituximab plus cytotoxic chemotherapy (1), and observation alone(2). Although 8 patients achieved response, 2 patients suffered a relapse of EBV-PTLD. With a median follow up of 27.5 (4.1-47.7) months, 2-year overall survival was 46.9% after diagnosis of EBV-PTLD. Eight patients died and 4 are alive without relapse of EBV-PTLD. Causes of death were EBV-PTLD (n=2), relapse of underlying disease(3), infectious disease(2), and aGVHD(1). Conclusion Twelve cases of EBV-PTLD were identified in 825 transplants. Cumulative incidence of EBV-PTLD at 2 years was 1.5%. The incidence of EBV-PTLD after CB transplant was higher than that after non CB transplant, although we have to take into consideration that patients feature was different between them. Response to rituximab and/or reduction of IST was observed in 8 patients with a 2-year overall survival rate of 46.9%. Patients with prior aGVHD and with longer duration of immunosuppressive therapy may have an increased risk of developing EBV-PTLD. Since the initial manifestations were often equivocal, and survival rate after diagnosis is not high, having EBV-PTLD in mind as one of the possibilities is critical for prompt diagnosis. Disclosures: No relevant conflicts of interest to declare.

[Background] Signaling through the Notch receptors, triggered by the binding of ligands expressed on neighboring cells, has a key role in determining cell fate in a variety of cell lineages, including lymphocytes. The physiologic roles of two of the four mammalian Notch genes, Notch1 and Notch2, have been clarified in mouse models. Notch1 is preferentially expressed in immature T cells and is essential for specification of early hematopoietic progenitors toward the T-cell fate and for early T-cell development in the thymus. In contrast, Notch2 is preferentially expressed in mature B cells and is required for the generation of a mature B-cell subset, known as splenic marginal zone B (MZB) cells. Deregulation of Notch1 function results in the development of T-cell acute lymphoblastic leukemia (T-ALL) in a number of mouse experimental models, and more importantly, more than 50% of childhood and 30% to 40% of adult human T-ALL cases carry Notch1 mutations that lead to deregulated activation of Notch signaling, indicating that accelerated Notch signaling contributes to the development of human neoplasms. [Results and Discussion] We screened Notch2 gene mutations at the heterodimerization and PEST domains in 109 B-cell lymphoma samples, and found mutations in 5 samples, all of which were diffuse large B-cell lymphomas (DLBCL; in DLBCL, 5 of 63 samples, ∼8%). These mutations lead to partial or complete deletion of the PEST domain, or a single amino acid substitution at the C-terminus of Notch2 protein. All five DLBCL cases with Notch2 mutations were uniformly immunohistochemically negative for CD10 and positive for BCL6 and MUM-1, whereas only 10 out of 24 Notch2 mutation-negative subjects showed this staining pattern. This observation might imply a link between Notch2 mutations and a fraction of non-germinal center B-cell-like DLBCL (non-GCB-DLBCL), according to the immunohistchemistry-based DLBCL subclassification. Interestingly, high-density oligonucleotide microarray analysis revealed that two of the five Notch2 mutation-carrying samples had an increased copy number of the mutated Notch2 allele, and in another sample of the five the total copy number of the Notch2 allele was increased. Furthermore, in the Notch activation-sensitive luciferase reporter assay in vitro, mutant Notch2 receptors showed increased activity compared with wild-type Notch2. These findings implicate Notch2 gain-of-function mutations in the pathogenesis of a subset of B-cell lymphomas, and suggest broader roles for Notch gene mutations in human cancers.

Pyothorax-associated lymphoma (PAL) is a lymphoproliferative disorder developing in the pleural cavity after a long-standing history of pyothorax. The pathogenesis, clinical features and optimal treatment have not been clarified. To investigate clinicopathological features of pyothorax-associated lymphoma (PAL), we examined medical records of 98 patients (88 males and 10 females) with PAL at a median age of 70 (range, 51–86). Seventy-nine patients had a history of artificial pneumothorax. Median interval between diagnosis and artificial pneumothorax was 43 years (range, 19–64). At diagnosis, performance status was 0–1 (n=56) and 2–4 (n=42). Clinical stages were I (n=42), II (n=26), III (n=8) and IV (n=22). In situ hybridization using a probe for EBV-encoded RNA-1 demonstrated the presence of the EBV genome in the nucleus of tumor cells in 28 of 29 (88%) patients. Immunohistochemical studies revealed that 12 of 14 (86%) and 11 of 17 (65%) were positive for EBNA-2 and LMP-1, respectively. Seventeen were treated supportively. The other 81 received aggressive treatments; chemotherapy (n=52), radiotherapy (n=7), surgery (n=4) and combination (n=18). Response rates to chemotherapy, radiotherapy, and chemoradiotherapy were 56%, 71%, and 83%, respectively. Five-year overall survival was 0.35 (95% confidence interval, 24–45%). The 5-year overall survival rates were 0.47 (95% CI, 0.30– 0.63), 0.35 (95% CI, 0.16– 0.54) and 0.15 (95% CI, 0.04–0.33) in patients with stages I, II and I-IV disease, respectively (Figure 1). Overall survival are different among the three groups (p Figure Figure

Summary The discovery of induced pluripotent stem cells (iPSCs) has created promising new avenues for therapies in regenerative medicine. However, the tumorigenic potential of undifferentiated iPSCs is a major safety concern for clinical translation. To address this issue, we demonstrated the efficacy of suicide gene therapy by introducing inducible caspase-9 (iC9) into iPSCs. Activation of iC9 with a specific chemical inducer of dimerization (CID) initiates a caspase cascade that eliminates iPSCs and tumors originated from iPSCs. We introduced this iC9/CID safeguard system into a previously reported iPSC-derived, rejuvenated cytotoxic T lymphocyte (rejCTL) therapy model and confirmed that we can generate rejCTLs from iPSCs expressing high levels of iC9 without disturbing antigen-specific killing activity. iC9-expressing rejCTLs exert antitumor effects in vivo. The system efficiently and safely induces apoptosis in these rejCTLs. These results unite to suggest that the iC9/CID safeguard system is a promising tool for future iPSC-mediated approaches to clinical therapy., Graphical Abstract, Highlights • iPSC-derived rejuvenated CTLs are effective against EBV-induced tumors in vivo • Rejuvenated CTLs are implemented with an inducible caspase-9 (iC9)-based suicide system • Upon induction, the iC9 system efficiently leads to apoptosis in rejuvenated CTLs • The iC9-based system provides a safeguard for future iPSC-mediated cell therapy, In this article, Nakauchi and colleagues show that iPSC-derived rejuvenated CTLs (rejCTLs) implemented with an inducible caspase-9 (iC9)-based suicide system are effective against EBV-induced tumors in vivo. Upon induction, the iC9-based system efficiently and safely leads to apoptosis in these rejCTLs in vitro and in vivo and provides a safeguard for future iPSC-mediated cell therapy.

Background Although gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, they are very rare. This study evaluated clinical and histopathological characteristics of duodenal GISTs to identify factors useful in predicting prognosis for patients with these tumors. Methods A retrospective study was performed on 20 patients who had undergone surgery between 1987 and 2009 for duodenal GISTs. Clinical, histopathological, and immunohistochemical data were evaluated. Survival analyses were conducted using Kaplan-Meier estimates. Results In 12 patients (60%), duodenal GISTs were diagnosed incidentally. Eight cases (40%) were classified as high risk grade GISTs. Skeinoid fibers (SkF), which are eosinophilic globular hyaline deposits in the extracellular interstitium of the tumor, were found in 12 patients. Skeinoid fibers were not recognized in 8 cases, and these included 3 cases (37.5%) where tumors recurred after surgery and the patient died. Tumors without SkF were larger (81 ± 92 vs. 23 ± 8 mm, P < 0.001) and had a higher mitotic count (224.0 ± 336.6 vs. 0.0 ± 0.0 /50 high-power field, P < 0.001) than those with SkF. Survival time was shorter in patients with tumors lacking SkF (52.9 ± 50.7 vs. 108.9 ± 86.5 months, P = 0.019). Conclusions We have identified clinical and histopathological characteristics that were useful in predicting the prognosis of patients with duodenal GISTs. In this study, 60% of the tumors were found incidentally, SkF were not recognized in tumors from 40% of patients, and all cases of post-operative tumor recurrence and death occurred in this subgroup of patients.