SREBP signaling is essential for effective B cell responses.

Our previous study using systems vaccinology identified an association between the sterol regulatory binding protein (SREBP) pathway and humoral immune response to vaccination in humans. To investigate the role of SREBP signaling in modulating immune responses, we generated mice with B cell- or CD11c+ antigen-presenting cell (APC)-specific deletion of SCAP, an essential regulator of SREBP signaling. Ablation of SCAP in CD11c+ APCs had no effect on immune responses. In contrast, SREBP signaling in B cells was critical for antibody responses, as well as the generation of germinal centers,memory B cells and bone marrow plasma cells. SREBP signaling was required for metabolic reprogramming in activated B cells. Upon mitogen stimulation, SCAP-deficient B cells could not proliferate and had decreased lipid rafts. Deletion of SCAP in germinal center B cells using AID-Cre decreased lipid raft content and cell cycle progression. These studies provide mechanistic insights coupling sterol metabolism with the quality and longevity of humoral immunity.

Signet-ring cell lymphoma: clinicopathologic, immunohistochemical, and fluorescence in situ hybridization studies of 7 cases.

CONTEXT: Signet-ring cell lymphoma (SRCL) is a rare morphologic variant of non-Hodgkin lymphoma. Although it was initially reported as a rare morphologic variant of follicular lymphoma (FL), SRCL has to date been described in most types of non-Hodgkin lymphoma, mostly as single-case reports. OBJECTIVE: To study SRCL systematically by immunohistochemical stains and fluorescent in situ hybridization analyses. DESIGN: Seven SRCL cases were stained for CD3, CD5, CD20, PAX-5, CD10, CD21, CD23, cyclin D1, BCL2, BCL6, Ki-67, and MUM-1, and were analyzed by fluorescent in situ hybridization for BCL2, BCL6, MYC, and MALT1 rearrangements. Clinical information and patient outcome were reviewed in all patients. RESULTS: The patients were 3 women and 3 men, ranging in age from 31 to 75 years (average 60.3 years). The lesions involved lymph nodes, tonsil, parotid gland, soft tissue, and breast. There were 4 FLs, 1 diffuse large B-cell lymphoma (DLBCL), 1 DLBCL with FL, and 1 DLBCL with marginal zone lymphoma. All cases had typical signet-ring cell morphology. They were positive for CD20 and BCL-2, and had low-to-intermediate Ki-67 proliferation index (10%-40%) except in the parotid DLBCL with FL (70%). BCL-6 was detected in all but 1 FL (6/7). Fluorescent in situ hybridization detected IGH/BCL2 translocation in 1 FL, increased BCL6 copy number in another FL, BCL6 rearrangement, and increased copy number of MYC and MALT1 in the DLBCL with marginal zone lymphoma. CONCLUSIONS: The FL with signet-ring cell morphology (1/5) tends to lack IGH/BCL2 translocation, and an extended immunohistochemical study is recommended for correct diagnosis and classification of SRCL.

Loss of Asxl1 leads to myelodysplastic syndrome-like disease in mice.

ASXL1 is mutated/deleted with high frequencies in multiple forms of myeloid malignancies, and its alterations are associated with poor prognosis. De novo ASXL1 mutations cause Bohring-Opitz syndrome characterized by multiple congenital malformations. We show that Asxl1 deletion in mice led to developmental abnormalities including dwarfism, anophthalmia, and 80% embryonic lethality. Surviving Asxl1(-/-) mice lived for up to 42 days and developed features of myelodysplastic syndrome (MDS), including dysplastic neutrophils and multiple lineage cytopenia. Asxl1(-/-) mice had a reduced hematopoietic stem cell (HSC) pool, and Asxl1(-/-) HSCs exhibited decreased hematopoietic repopulating capacity, with skewed cell differentiation favoring granulocytic lineage. Asxl1(+/-) mice also developed mild MDS-like disease, which could progress to MDS/myeloproliferative neoplasm, demonstrating a haploinsufficient effect of Asxl1 in the pathogenesis of myeloid malignancies. Asxl1 loss led to an increased apoptosis and mitosis in Lineage(-)c-Kit(+) (Lin(-)c-Kit(+)) cells, consistent with human MDS. Furthermore, Asxl1(-/-) Lin(-)c-Kit(+) cells exhibited decreased global levels of H3K27me3 and H3K4me3 and altered expression of genes regulating apoptosis (Bcl2, Bcl2l12, Bcl2l13). Collectively, we report a novel ASXL1 murine model that recapitulates human myeloid malignancies, implying that Asxl1 functions as a tumor suppressor to maintain hematopoietic cell homeostasis. Future work is necessary to clarify the contribution of microenvironment to the hematopoietic phenotypes observed in the constitutional Asxl1(-/-) mice.

Lymphoproliferative Neoplasms With Plasmablastic Morphology.

CONTEXT.­: Plasmablastic morphology can be seen in several uncommon lymphoproliferative neoplasms. Sometimes it is difficult to distinguish these neoplasms from each other. OBJECTIVE.­: To review the current understanding of major lymphoproliferative neoplasms with plasmablastic morphology; summarize the clinical, morphologic, immunophenotypic, cytogenetic, and molecular characteristics of each disease entity; and highlight a practical approach for differential diagnosis. DATA SOURCES.­: Peer-reviewed medical literature and the authors' personal experience. CONCLUSIONS.­: Plasmablastic lymphoma; plasmablastic myeloma; primary effusion lymphoma; human herpesvirus 8-positive diffuse large B-cell lymphoma, not otherwise specified; and anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma are major lymphoproliferative neoplasms with plasmablastic morphology. These neoplasms share many common morphologic and immunophenotypic characteristics. Definitive diagnosis requires a thorough understanding of disease phenotype and diagnostic criteria of each category. Recognition of expression pattern of Epstein-Barr virus-encoded small RNA, human herpesvirus 8, and ALK in these neoplasms is critical for diagnosis in cases with typical presentation. Additional ancillary studies and clinical findings may help in difficult cases.

Update on the Classification of and Diagnostic Approaches to Mature T-Cell Lymphomas.

CONTEXT.­: In the 2017 revised World Health Organization classification of tumors of hematopoietic and lymphoid tissues, some mature T-cell lymphomas were reclassified and a few new provisional entities were established based on new data from clinical and laboratory studies. T follicular helper cell lymphoma is identified by T follicular helper cell markers. Anaplastic large cell lymphoma, ALK negative, is a better-defined entity based on genetic abnormalities, and breast implant-associated anaplastic large cell lymphoma is recognized as a provisional entity. The gastrointestinal T-cell lymphomas are reclassified, with addition of a new provisional entity, indolent T-cell lymphoproliferative disorder of the gastrointestinal tract, characterized by an indolent clinical course. OBJECTIVE.­: To review the diagnostic approaches to reclassified and newly established entities of mature T-cell lymphomas, focusing on significant immunophenotypic features and molecular genetic abnormalities. Relevant new discoveries after the publication of the 2017 World Health Organization classification are included. DATA SOURCES.­: Information from the literature most relevant to the 2017 World Health Organization revised classification and publications after 2016. CONCLUSIONS.­: Incorporating clinical, morphologic, and immunophenotypic features usually provides sufficient evidence to reach a preliminary diagnosis of mature T-cell lymphoma. Molecular genetic studies can be very helpful for the final diagnosis and classification, especially in challenging cases. Some molecular genetic features have been found in breast implant-associated anaplastic large cell lymphoma, distinct from anaplastic large cell lymphoma, ALK negative. Immunohistochemical staining of 4 markers may enable further subtyping of peripheral T-cell lymphomas.

Asparagine bioavailability regulates the translation of MYC oncogene.

Amino acid restriction has recently emerged as a compelling strategy to inhibit tumor growth. Recent work suggests that amino acids can regulate cellular signaling in addition to their role as biosynthetic substrates. Using lymphoid cancer cells as a model, we found that asparagine depletion acutely reduces the expression of c-MYC protein without changing its mRNA expression. Furthermore, asparagine depletion inhibits the translation of MYC mRNA without altering the rate of MYC protein degradation. Of interest, the inhibitory effect on MYC mRNA translation during asparagine depletion is not due to the activation of the general controlled nonderepressible 2 (GCN2) pathway and is not a consequence of the inhibition of global protein synthesis. In addition, both the 5' and 3' untranslated regions (UTRs) of MYC mRNA are not required for this inhibitory effect. Finally, using a MYC-driven mouse B cell lymphoma model, we found that shRNA inhibition of asparagine synthetase (ASNS) or pharmacological inhibition of asparagine production can significantly reduce the MYC protein expression and tumor growth when environmental asparagine becomes limiting. Since MYC is a critical oncogene, our results uncover a molecular connection between MYC mRNA translation and asparagine bioavailability and shed light on a potential to target MYC oncogene post-transcriptionally through asparagine restriction.

Myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are hematopoietic neoplasms characterized by an ineffective hematopoiesis associated with cytopenia(s), functional abnormalities of bone marrow lineages, morphologic dysplasia, and a progression to acute myeloid leukemia. The pathogenesis of MDS is exceedingly complex and involves the hematopoietic stem cells/hematopoietic precursors, bone marrow microenvironment, and complex interaction between these components. The diagnostic strategy in MDS has evolved significantly over the years from a strategy based almost exclusively on peripheral blood smear and bone marrow aspirate morphology to the integrated approach used in the 2001 and 2008 World Health Organization (WHO) classification schemes. In parallel with the diagnostic approach, evolution has occurred in the prognostic assessment and evaluation of treatment response. The prognostic assessment now includes both disease-related factors and patient-specific characteristics such as nonhematologic comorbidities. All these developments are particularly important considering the ever-increasing treatment options available for MDS. This review focuses on the diagnostic approach to MDS and highlights recent developments in the pathogenesis as well as select clinical advances. We present the overview of the minimal diagnostic criteria for a diagnosis of MDS, the WHO classification scheme, and briefly address the risk stratification.

A Panel of Five-lncRNA Signature as a Potential Biomarker for Predicting Survival in Gastric and Thoracic Cancers.

Dysfunctional long non-coding RNAs (lncRNAs) have been found to have carcinogenic and/or tumor inhibitory effects in the development and progression of cancer, suggesting their potential as new independent biomarkers for cancer diagnosis and prognosis. The exploration of the relationship between lncRNAs and the overall survival (OS) of different cancers opens up new prospects for tumor diagnosis and treatment. In this study, we established a five-lncRNA signature and explored its prognostic efficiency in gastric cancer (GC) and several thoracic malignancies, including breast invasive carcinoma (BRCA), esophageal carcinoma, lung adenocarcinoma, lung squamous cell carcinoma (LUSC), and thymoma (THYM). Cox regression analysis and lasso regression were used to evaluate the relationship between lncRNA expression and survival in different cancer datasets from GEO and TCGA. Kaplan-Meier survival curves indicated that risk scores characterized by a five-lncRNA signature were significantly associated with the OS of GC, BRCA, LUSC, and THYM patients. Functional enrichment analysis showed that these five lncRNAs are involved in known biological pathways related to cancer pathology. In conclusion, the five-lncRNA signature can be used as a prognostic marker to promote the diagnosis and treatment of GC and thymic malignancies.

Neutrophils compromise retinal pigment epithelial barrier integrity.

We hypothesized that neutrophils and their secreted factors mediate breakdown of the integrity of the outer blood-retina-barrier by degrading the apical tight junctions of the retinal pigment epithelium (RPE). The effect of activated neutrophils or neutrophil cell lysate on apparent permeability of bovine RPE-Choroid explants was evaluated by measuring [3H] mannitol flux in a modified Ussing chamber. The expression of matrix metalloproteinase- (MMP-) 9 in murine peritoneal neutrophils, and the effects of neutrophils on RPE tight-junction protein expression were assessed by confocal microscopy and western blot. Our results revealed that basolateral incubation of explants with neutrophils decreased occludin and ZO-1 expression at 1 and 3 hours and increased the permeability of bovine RPE-Choroid explants by >3-fold (P < .05). Similarly, basolateral incubation of explants with neutrophil lysate decreased ZO-1 expression at 1 and 3 hours (P < .05) and increased permeability of explants by 75%. Further, we found that neutrophils prominently express MMP-9 and that incubation of explants with neutrophils in the presence of anti-MMP-9 antibody inhibited the increase in permeability. These data suggest that neutrophil-derived MMP-9 may play an important role in disrupting the integrity of the outer blood-retina barrier.

Myeloid neoplasm with a novel cryptic PDGFRB rearrangement detected by next-generation sequencing.

Rearrangements of PDGFRB are defining cytogenetic abnormalities seen in "Myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRB" and are generally evident by common cytogenetic methods. Here we present an unique case in which karyotyping and fluorescence in situ hybridization (FISH) analysis were negative, and the PDGFRB rearrangement was detected by next-generation sequencing (NGS) analysis. The patient presented with approximately one-year history of leukocytosis including neutrophilia, eosinophilia, basophilia and granulocytic left shift. Bone marrow biopsy revealed a hypercellular marrow with panmyelosis, eosinophilia and mast cell hyperplasia. Blasts were not increased. Ancillary studies revealed a normal karyotype and absence of BCR-ABL1 fusion gene. NGS identified AFAP1L1-PDGFRB fusion, which was confirmed by polymerase chain reaction amplification followed by direct Sanger sequencing. The patient was treated with imatinib and showed normalization of peripheral blood leukocytosis, which lasted for at least six months. This case highlights that cytogenetics/FISH study alone may be insufficient to detect all PDGFRB rearrangement, which is critical for the patient's management. We suggest that molecular analysis capable of detecting fusion genes should be performed in all similar cases.

Hepatic involvement by T-cell neoplasms: a clinicopathologic study of 40 cases.

Hepatic involvement by a T-cell neoplasm is rare and often challenging to diagnose in liver biopsies. We collected 40 cases of T-cell neoplasms diagnosed in the liver from five large academic institutions to assess the clinicopathologic features. The patients included 11 women and 29 men, with a median age of 54 (range: 2-75) years and a high mortality rate (31/37, 83.8%). Fourteen (35%) patients were diagnosed with hepatosplenic T-cell lymphoma (HSTCL), 13 (32.5%) peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), and 13 (32.5%) other types of T-cell neoplasms. Patients with HSTCL were much younger and had worse survival than PTCL-NOS and other T-cell neoplasms (P < 0.05). On imaging studies, 20 cases (50%) showed abnormalities, including 10 with mass lesions that correlated with normal or cholestatic pattern enzyme elevation. Histomorphological analysis revealed four main patterns; with the exception of mass forming lesions (pattern 4; n = 8), cases with sinusoidal predominant (pattern 1; n = 12), portal predominant with sinusoidal infiltrates (pattern 2; n = 13) or lobular aggregates (pattern 3; n = 5) demonstrated small to medium lymphocytes resembling a reactive/inflammatory process. In addition, we described two cases of T-cell large granular lymphocytic leukemia that mimicked HSTCL, and a case of aggressive post-transplant lymphoproliferative disorder that developed after chronic Epstein-barr virus (EBV) infection, suggesting the importance of EBV testing in some lymphoma cases. As the largest cohort of T-cell neoplasms in liver, our study provides critical data on disease frequency, distribution, and clinicopathologic features that are essential for accurate diagnosis.

CD23 expression in mantle cell lymphoma is associated with CD200 expression, leukemic non-nodal form, and a better prognosis.

Mantle cell lymphoma (MCL) is usually CD23 negative, a feature helpful in distinguishing MCL from chronic lymphocytic leukemia/small lymphocytic lymphoma. However, a subset of MCL cases can be CD23+. Limited data are available regarding the clinicopathological features and prognosis of patients with CD23+ MCL. In this study, we reviewed 798 cases of MCL and identified 103 (13%) that were CD23+ by flow cytometry, all of which were positive for cyclin D1 and/or associated with CCND1/IGH. In all cases of CD23+ MCL, CD23 expression was dim partial or dim, unlike moderate to bright CD23 expression observed in chronic lymphocytic leukemia/small lymphocytic lymphoma. The clinicopathological features and outcome of patients with CD23+ MCL were compared with 240 patients with typical MCL negative for CD23. Patients with CD23+ MCL more often had an elevated leukocyte count (33% versus 18%, P = .009), bone marrow involvement (89% versus 78%, P = .02), stage 4 disease (87% versus 77%, P = .03), and a leukemic presentation (42% versus 11%, P = .0001). CD23+ MCL was also more often positive for CD200 (17% versus. 4.6%, P = .0005) and less commonly positive for SOX11 (55% versus. 74%, P = .027). All other clinicopathological features were similar. With similar treatment regimens and observation times, patients with CD23+ MCL had a significant better overall survival (P = .02) and progression-free survival (P = .029). In conclusion, CD23 expression was observed in 13% of MCL cases and is associated with a better prognosis in patients with MCL. CD23 is associated with leukocytosis, a leukemic presentation, bone marrow involvement, CD200 expression, and a lower frequency of SOX11 positivity.

Mantle Cell Lymphoma With Mantle Zone Growth Pattern.

OBJECTIVES: To characterize the clinical and pathologic features of mantle cell lymphoma with mantle zone growth pattern (MCL-MZGP). METHODS: The clinicopathologic data from 35 cases of MCL-MZGP obtained in 12 centers were analyzed. RESULTS: The patients with MCL-MZGP typically sought treatment at high clinical stages (81%). Intriguingly, 40% (14/35) of cases were incidentally noted. The lymph nodes with MCL-MZGP showed preserved architecture and expanded mantles containing lymphoma cells with classic or small cell cytology. MCL-MZGP was positive for BCL2 (96%, bright), CD5 (82%, moderate), cyclin D1 (100%), and SOX11 (89%). Clinically, our study revealed no significant difference in the overall survival between patients managed with observation alone and those who received chemotherapy. CONCLUSIONS: MCL-MZGP was often incidentally identified and resembled reactive mantles. Therefore, recognition of this unusual morphology emphasizes the utility of cyclin D1 immunostain in the cases with suspicious morphology. However, the clinical significance of these findings is still unclear.

N-(4-hydroxyphenyl) retinamide augments laser-induced choroidal neovascularization in mice.

PURPOSE: To evaluate the effect of N-4-hydroxyphenyl retinamide (4-HPR) on experimental laser-induced choroidal neovascularization (CNV) and on the expression and secretion of relevant growth factors by cultured human retinal pigment epithelial (RPE) cells. METHODS: CNV was induced by laser photocoagulation in C57BL/6 mice. 4-HPR (0.2 or 1 mg) or vehicle, was injected intraperitoneally twice daily for 14 days. Plasma and tissue levels of 4-HPR were measured by HPLC. CNV was evaluated by fluorescein angiography, histology, and quantitative confocal analysis of isolectin B4 histochemistry on days 7 and 14. Induction of apoptosis and expression and secretion of growth factors was studied in 4-HPR-treated RPE cultures. RESULTS: Mice treated with 4-HPR exhibited time- and dose-dependent increases in plasma and tissue 4-HPR levels. CNV lesions showed increased volume with increased vascular leakage and contained fewer lesion-associated RPE in treated versus untreated mice. Treatment of nonpolarized RPE cultures with 4-HPR in the presence of serum resulted in RPE apoptosis; however, apoptosis was minimal in similarly treated highly polarized RPE. Treatment of RPE cells with 4-HPR resulted in the upregulation of VEGF-A and -C (P < 0.05) and Ang-1 (P < 0.01) mRNA and increased secretion of VEGF-A and -C (P < 0.05), whereas pigment epithelium-derived growth factor (PEDF) and thrombospondin (TSP)-1 mRNA expression and secretion were downregulated (P < 0.05). CONCLUSIONS: 4-HPR increases lesion size and leakage in laser-induced CNV and is associated with the upregulation of key proangiogenic factors and the downregulation of antiangiogenic factors. Consistent with the preferential loss of RPE in CNV lesions in vivo, 4-HPR induces apoptosis of nonpolarized RPE in the presence of serum.

Live remote digital microscopy in peripheral blood smear evaluation: Intraobserver concordance and experience.

INTRODUCTION: Peripheral blood smear (PBS) review is a routine laboratory test which requires pathologist's interpretation when abnormal indices, atypical cells, or critical findings are identified. Real-time remote digital microscopy (DM) can potentially facilitate rapid review when an on-site pathologist is not available. Herein, we assess intraobserver concordance of PBS evaluation with light microscopy (LM) and DM using VisionTek M6 robotic DM and TeamViewer imaging software. METHODS: Thirty-seven de-identified PBS slides were evaluated by five reviewers. Slides were loaded on a VisionTek M6 robotic microscope at an off-site laboratory and evaluated remotely via TeamViewer software. Reviewers recorded interpretation, time required for interpretation (in minutes), imaging quality (score 0-3), and confidence of interpretation (score 0-3). Other relevant information associated with DM evaluation was also documented. Slides were subsequently evaluated using LM after washout interval. The intraobserver variation of results for impression, digital slide quality, minutes to interpretation, and confidence of interpretation was compared between DM and LM. RESULTS: The intraobserver concordance between LM and DM was 93%, with nine discordant interpretations among 135 evaluations under each review modality, respectively. Although reviewers spent more time under DM mode (5 min/slide) than LM mode (2.5 min/slide), the reviewers felt the DM provided sufficient image quality and the confidence levels of reviewers on slide interpretation were comparable between DM (2.6/3) and LM (2.8/3). CONCLUSION: There was a high level of intraobserver concordance and comparable interpretation confidence between DM and LM. DM can be a useful methodology for off-site pathologist's review of PBS.

Fine needle aspiration evaluation of pancreatic lymphoma: A retrospective study of 25 cases in a single institution.

BACKGROUND: Accurate diagnosis of pancreatic lymphoma is crucial for clinical management. We evaluate the role of fine-needle aspiration (FNA) in the diagnosis of pancreatic lymphoma with the aid of flow cytometry and/or immunohistochemistry on the cell block. METHODS: Cases of pancreatic lymphoma were collected by searching our pathology laboratory information system over a period of 16 years. The clinical findings, cytologic features, and immunophenotypic results were reviewed. The diagnoses of FNA were correlated with surgical specimens in a subset of FNA cases. RESULTS: A total of 25 FNA cases of pancreatic lymphoma were included. The most common type of pancreatic lymphoma was large B cell lymphoma followed by follicular lymphoma. With the aid of flow cytometry and immunohistochemical work-up on cell block, 72% (18/25) of the cases were diagnosed as lymphoma and 16% of the cases (4/25) were diagnosed as suspicious for lymphoma by FNA. Only two cases (8%) including one false negative and one nondiagnostic aspirate missed the lymphoma diagnosis and 1 case (4%) was indeterminate by FNA evaluation. CONCLUSION: FNA demonstrated high accuracy in rendering diagnosis of pancreatic lymphoma. The overall sensitivity is 88% and the false negative and nondiagnostic rates are 4%, respectively. Further subtyping of certain lymphomas can be difficult due to the lack of architectural features of FNA specimens.