Induction Of Lymphomas Research Articles

High-Dose Methotrexate as CNS Prophylaxis in High-Risk Aggressive B-Cell Lymphoma.

CNS progression or relapse is an uncommon but devastating complication of aggressive B-cell lymphoma. There is no consensus regarding the optimal approach to CNS prophylaxis. This study was designed to determine whether high-dose methotrexate (HD-MTX) is effective at preventing CNS progression in patients at high risk of this complication. Patients age 18-80 years with aggressive B-cell lymphoma and high risk of CNS progression, treated with curative-intent anti-CD20-based chemoimmunotherapy, were included in this international, retrospective, observational study. Cause-specific hazard ratios (HRs) and cumulative risks of CNS progression were calculated according to use of HD-MTX, with time to CNS progression calculated from diagnosis for all patients (all-pts) and from completion of frontline systemic lymphoma induction therapy, for patients in complete response at completion of chemoimmunotherapy (CR-pts). Two thousand four hundred eighteen all-pts (HD-MTX; n = 425) and 1,616 CR-pts (HD-MTX; n = 356) were included. CNS International Prognostic Index was 4-6 in 83.4% all-pts. Patients treated with HD-MTX had a lower risk of CNS progression (adjusted HR, 0.59 [95% CI, 0.38 to 0.90]; P = .014), but significance was not retained when confined to CR-pts (adjusted HR, 0.74 [95% CI, 0.42 to 1.30]; P = .29), with 5-year adjusted risk difference of 1.6% (95% CI, -1.5 to 4.4; all-pts) and 1.4% (95% CI, -1.5 to 4.1; CR-pts). Subgroups were underpowered to draw definitive conclusions regarding the efficacy of HD-MTX in individual high-risk clinical scenarios; however, there was no clear reduction in CNS progression risk with HD-MTX in any high-risk subgroup. In this large study, high-risk patients receiving HD-MTX had a 7.2% 2-year risk of CNS progression, consistent with the progression risk in previously reported high-risk cohorts. Use of HD-MTX was not associated with a clinically meaningful reduction in risk of CNS progression.

Critical roles of non-coding RNAs in lifecycle and biology of Marek's disease herpesvirus.

Over the past two decades, numerous non-coding RNAs (ncRNAs) have been identified in different biological systems including virology, especially in large DNA viruses such as herpesviruses. As a representative oncogenic alphaherpesvirus, Marek's disease virus (MDV) causes an important immunosuppressive and rapid-onset neoplastic disease of poultry, namely Marek's disease (MD). Vaccinations can efficiently prevent the onset of MD lymphomas and other clinical disease, often heralded as the first successful example of vaccination-based control of cancer. MDV infection is also an excellent model for research into virally-induced tumorigenesis. Recently, great progress has been made in understanding the functions of ncRNAs in MD biology. Herein, we give a review of the discovery and identification of MDV-encoded viral miRNAs, focusing on the genomics, expression profiles, and emerging critical roles of MDV-1 miRNAs as oncogenic miRNAs (oncomiRs) or tumor suppressor genes involved in the induction of MD lymphomas. We also described the involvements of host cellular miRNAs, lincRNAs, and circRNAs participating in MDV life cycle, pathogenesis, and/or tumorigenesis. The prospects, strategies, and new techniques such as the CRISPR/Cas9-based gene editing applicable for further investigation into the ncRNA-mediated regulatory mechanisms in MDV pathogenesis/oncogenesis were also discussed, together with the possibilities of future studies on antiviral therapy and the development of new efficient MD vaccines.

Detection of Marek’s Disease Virus Serotypes 1, 2 and 3 in Poultry Flocks using PCR Technique in South-Western-Nigeria

Marek’s disease virus (MDV) causes immunosuppression and tumors in poultry. Lymphoma induction in Marek’s disease (MD) has been associated with serotype-1. The study employed the use of two-step-PCR with primers directed to gB-gene of MDV to determine and differentiate MDV-serotypes associated with MD-outbreaks in poultry-flocks using tissue samples with neoplastic lesions collected from carcasses during postmortem examination. A total of 58 different flocks categorized into pullets, broiler, turkey and duck suspected of MD were sampled using PCR-techniques. Forty three out of the 58 flocks sampled were positive for MDV employing first and nested PCR analysis using serotype-specific primer pairs in the nested PCR, 38 (65.5%), 22 (37.93%) and 20 (34.48%) were positive for MDV-serotypes 1, 2 and 3 respectively. The distribution of three serotypes of MDV was quite different among investigated poultry flocks. Fourteen (73.68%), 7 (36.84%) and 6 (31.57%) farms were positive for MDV-serotypes-1, 2 and 3 respectively in pullet flocks with age range between 8-20 weeks. In layer flocks, 22 (66.66%), 13 (39.39%) and 11 (33.33%) were positive for MDV-serotypes 1, 2 and 3. One broiler flock was positive for MDV-serotype-2 and 3, only one turkey flock positive for MDV-serotypes 1, 2 and 3, one duck farm was positive for MDV- serotype 1. Multiple infections involving two or three of the serotypes were observed in 8-20 weeks old pullets with 4 (21.1%) of the flocks showing MDV-1 and MDV-2, 3 (15.79%) with MDV-1 and 3 and 3 (15.79%) with all the three-serotypes. This study revealed increased virulence of MDV-serotypes-2 and 3 that have been classified as non-oncogenic in field MD-outbreaks.

Detection of Marek’s Disease Virus Serotypes 1, 2 and 3 in Poultry Flocks using PCR Technique in South-Western-Nigeria

Marek’s disease virus (MDV) causes immunosuppression and tumors in poultry. Lymphoma induction in Marek’s disease (MD) has been associated with serotype-1. The study employed the use of two-step-PCR with primers directed to gB-gene of MDV to determine and differentiate MDV-serotypes associated with MD-outbreaks in poultry-flocks using tissue samples with neoplastic lesions collected from carcasses during postmortem examination. A total of 58 different flocks categorized into pullets, broiler, turkey and duck suspected of MD were sampled using PCR-techniques. Forty three out of the 58 flocks sampled were positive for MDV employing first and nested PCR analysis using serotype-specific primer pairs in the nested PCR, 38 (65.5%), 22 (37.93%) and 20 (34.48%) were positive for MDV-serotypes 1, 2 and 3 respectively. The distribution of three-serotypes of MDV was quite different among investigated poultry-flocks. Fourteen (73.68%), 7 (36.84%) and 6 (31.57%) farms were positive for MDV-serotypes-1, 2 and 3 respectively in pullet flocks with age range between 8-20 weeks. In layer flocks, 22 (66.66%), 13 (39.39%) and 11 (33.33%) were positive for MDV-serotypes 1, 2 and 3. One broiler flock was positive for MDV-serotype-2 and 3, only one turkey flock positive for MDV-serotypes 1, 2 and 3, one duck farm was positive for MDV- serotype 1. Multiple infections involving two or three of the serotypes were observed in 8-20 weeks old pullets with 4 (21.1%) of the flocks showing MDV-1 and MDV-2, 3 (15.79%) with MDV-1 and 3 and 3 (15.79%) with all the three-serotypes. This study revealed increased virulence of MDV-serotypes-2 and 3 that have been classified as non-oncogenic in field MD-outbreaks.

Abstract 2377: microRNA expression profile in urinary exosomes is dependent on non-invasive lymphoma induction in mice

Abstract Lymphoma accounts for approximately 4% of cancers in the United States, with an estimated 20,910 number of deaths per year. The standard method of diagnosis and staging of lymphoma involves surgical biopsy of the tumor - a procedure that has many negative associated risks. Exosomes are extracellular vesicles secreted in biological fluids that can serve as “liquid biomarkers”. Identification of unique cancer-related biomarkers in urinary exosomes may provide a novel non-invasive and cost-effective tool for lymphoma diagnosis. Analyses of biomarkers obtained from urinary exosomes have been used to evaluate urological cancers, however, these methods have not yet been translated to non-urological pathologies, such as lymphomas. The objective for this study was to determine the profile of microRNAs (miRNAs) expressed in urinary exosomes of mice challenged with lymphoma and compare it to miRNAs identified in urinary exosomes of control mice. Male and female C57BL/6 mice, (tumor (+), n=12), were injected with either 2.5x105 mouse EL-4 lymphoma cells or phosphate-buffered saline (tumor (-), n=12). Tumor growth was monitored for 20 days. Urine was collected for 48 hours starting on day 17 and serum, tumor tissues, and organs were collected on day 20. Extraction of urinary exosomes was followed by total RNA isolation and RT-qPCR for which a set of PCR arrays consisting of 709 mouse-specific miRNA primers was used. Fold changes in miRNA expression were quantified using the ΔΔCt method. Mice developed tumors by day 13 with initial tumor appearance around day seven. There were no statistically significant differences between final tumor mass, body weight, or food and water intake in tumor (+) versus tumor (-) mice. RT-qPCR arrays of miRNAs extracted from urinary exosomes revealed 464 miRNAs that were differentially expressed between tumor (+) and tumor (-). 215 miRNAs were up-regulated, while 249 miRNAs were down-regulated in tumor (+) mice. These results will be compared to miRNAs from serum and tumor tissues to identify tumor-specific miRNAs that can be used for potential application in the clinical setting. Citation Format: Brittany Wilson, Rebekah Betar, Alexander Martin, Zackaria Niazi, Michael Boyer, Lori Winter, Victor Babich, Francesca Di Sole, Elitsa Ananieva. microRNA expression profile in urinary exosomes is dependent on non-invasive lymphoma induction in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2377.

Sarcoidosis-Lymphoma Syndrome Associated With Primary Thyroid Lymphoma: A Case Report

Background: Sarcoidosis is occasionally accompanied by hematologic malignancies, including lymphoma, called sarcoidosis-lymphoma syndrome. Although the mechanism underlying the induction of lymphomas is still unknown, understanding the immunological background of sarcoidosis could help explain the possible mechanisms of the induction of lymphomas. Case Presentation: A 52-year-old woman was diagnosed chronic thyroiditis with normal thyroid function. One year later, she underwent a screening chest radiograph and identified bilateral hilar adenopathy and mediastinum lymphadenopathy. Subsequent mediastinoscopy demonstrated sarcoidosis. Because of the lack of clinical symptoms, steroid treatment was not initiated and regular follow-up was performed. One and a half years after the diagnosis of chronic thyroiditis, she presented with rapid swelling of the thyroid gland. FDG-PET/CT showed intense uptake of FDG in the thyroid gland and multiple lymphadenopathy. Fine-needle aspiration (FNA) cytology of the thyroid gland was only suggestive of a lymphoproliferative disorder and did not provide a definitive diagnosis. Partial thyroidectomy was performed, and the pathology indicated diffuse large B-cell lymphoma (DLBCL) such as high-grade transformation of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma. The results of an examination of a paraffin block histopathology specimen by fluorescence in-situ hybridization (FISH) detected BCL6 rearrangement (3q27), which is the most common chromosomal abnormality in DLBCL. After the treatment with R-EPOCH (rituximab, etoposide, vincristine, doxorubicin, cyclophosphamide, and prednisone) chemotherapy, the thyroid gland enlargement has improved markedly, while the lymph nodes remained swelling, that suggested lymph node involvements were due to sarcoidosis. Conclusions: Rapid swelling of the thyroid gland in the setting of chronic thyroiditis should raise suspicion for thyroid lymphoma. Furthermore, our present case might suggest that sarcoidosis accelerate the development and high-grade transformation of thyroid lymphoma. To our knowledge, this is the first reported case of sarcoidosis and primary thyroid lymphoma in the same patient.

PERIANAL INFECTIOUS COMPLICATIONS IN PATIENTS WITH GRANULOCYTOPENIA AND HAEMATOLOGICAL MALIGNANCIES

AIM : to study the perianal infection (PI) in patients with granulocytopaenia (GCP) and hematological malignancies (HM). PATIENTS AND METHODS: the prospective study (2016-1018) includes 95 episodes of PI in 76 patients with HM (male/female 35/44; mean age of 35 (17-69)). 43(54.4%) of the patients were detected to develop acute leukemia (AML – 34 (43%); ALL – 9(11.4%); NHL – 17(21.5%). The comparison of PI episodes within the GCP period (number of granulocytes less than 0.5x10 9 /l) and without it was done. RESULTS: PI episodes within the period of GCP were significantly much more often than those without GCP (77.9% vs 22.1%, relative risk 3.5 (95% CI: 2.4-5.2). The biggest number of PI episodes in the setting of GCP was registered within the period of chemotherapy (ChT): in the phase of consolidation (28.4%) and induction (13.3%) of acute leukemia ChT and lymphomas’ ChT (20.3%). Anal fissures were the most frequent source of PI within GCP period (66.2% vs 19.1% without GCP, p<0.001). Inflammatory changes in perianal tissues were clinical features of PI in the setting of GCP in 89.2% of the cases: inflammatory mass in 71.6% (vs 23.8% without GCP, p<0.001), abscess in 8.1% (vs 66.7% without GCP, p<0.001). In 10.8% of the cases of PI with GCP only perianal pain and fever were registered. No tissues change was detected with the lowest WBC count (Me 0.2 (0.1-0.5) x10 9 /l). Bloodstream infections were detected in 15 (20.3%) episodes within the period of GCP only, of them in 6 (8.1%) cases the species matching of microorganisms in blood and in rectum was noticed. Within the period of GCP antibacterial therapy was carried out in 98.6% of the cases: antibacterial therapy alone was applied in 87.8% of the episodes (vs 7.2% without GCP, p<0.001); both antibacterial therapy and surgical treatment were carried out in 10.8% (vs 61.9% without GCP, p<0.001) of the cases. Mean duration of antibiotic treatment of patients with GCP was drastically longer in the group of postoperative patients in comparison with the group of those who had conservative treatment (25.5 vs 15.1 days, p=0.05). Antimicrobial therapy within GCP period resulted into inflammation regress in 83.1% of the cases; abscess or fistula formation, hence surgical treatment in 13.8% of the cases; progression of infection in 3.1% of the cases. Increase of GCP duration up to 30 and more days is connected with bacteremia rate increase (12.5% vs 28%, p<0.05); combinations of PI with other infections (25% vs 52%, p<0.05); requirement of antimicrobial therapy modification (16.7% vs 40%, p<0.05). CONCLUSION: GCP significantly raises risk of PI. PI that develops in the setting of GCP, is characterized by abnormal, often low clinical manifestations and high risk of sepsis. Invasion of microorganisms through affected tissue seals is the basic mechanism of perianalinfection within the period of GCP. Antibacterial therapy is the prior method of PI treatment in the settings of GCP; antibacterial therapy efficiency is 83.1%. Need for surgery in the period of GCP is associated with the infectious episode and antibacterial therapy duration increase. Lengthening of GCP is a negative predictor in PI treatment.

Potential anti-EBV effects associated with elevated interleukin-21 levels: a case report

BackgroundGerminal center derived memory B cells and plasma cells constitute, in health and during EBV reactivation, the largest functional EBV reservoir. Hence, by reducing germinal center derived formation of memory B cells and plasma cells, EBV loads may be reduced. Animal and in-vitro models have shown that IL-21 can support memory B and plasma cell formation and thereby potentially contribute to EBV persistence. However, IL-21 also displays anti-viral effects, as mice models have shown that CD4+ T cell produced IL-21 is critical for the differentiation, function and survival of anti-viral CD8+ T cells able to contain chronic virus infections.Case presentationWe present immunological work-up (flow-cytometry, ELISA and genetics) related to a patient suffering from a condition resembling B cell chronic active EBV infection, albeit with moderately elevated EBV copy numbers. No mutations in genes associated with EBV disease, common variable immunodeficiency or pertaining to the IL-21 signaling pathway (including hypermorphic IL-21 mutations) were found. Increased (> 5-fold increase 7 days post-vaccination) CD4+ T cell produced (p < 0.01) and extracellular IL-21 levels characterized our patient and coexisted with: CD8+ lymphopenia, B lymphopenia, hypogammaglobulinemia, compromised memory B cell differentiation, absent induction of B-cell lymphoma 6 protein (Bcl-6) dependent peripheral follicular helper T cells (pTFH, p = 0.01), reduced frequencies of peripheral CD4+ Bcl-6+ T cells (p = 0.05), compromised plasmablast differentiation (reduced protein vaccine responses (p < 0.001) as well as reduced Treg frequencies. Supporting IL-21 mediated suppression of pTFH formation, pTFH and CD4+ IL-21+ frequencies were strongly inversely correlated, prior to and after vaccination, in the patient and in controls, Spearman’s rho: − 0.86, p < 0.001.ConclusionsTo the best of our knowledge, this is the first report of elevated CD4+ IL-21+ T cell frequencies in human EBV disease. IL-21 overproduction may, apart from driving T cell mediated anti-EBV responses, disrupt germinal center derived memory B cell and plasma cell formation, and thereby contribute to EBV disease control.

Iannis Aifantis: An accidental scientist.

Iannis Aifantis is a principal investigator at NYU Langone Medical Center, and his laboratory works on the molecular mechanisms that drive normal stem cell differentiation and malignant transformation. Specifically, they're interested in the genomic, epigenetic, and proteomic regulation of hematopoietic stem cell differentiation and the induction of leukemia and lymphoma; some of their basic research has led to clinical trials in leukemia and myelodysplastic syndromes. I chatted with Iannis to find out about his career in science so far.

Avian oncogenic herpesvirus antagonizes the cGAS-STING DNA-sensing pathway to mediate immune evasion.

The cellular DNA sensor cGMP-AMP synthase (cGAS) detects cytosolic viral DNA via the stimulator of interferon genes (STING) to initiate innate antiviral response. Herpesviruses are known to target key immune signaling pathways to persist in an immune-competent host. Marek’s disease virus (MDV), a highly pathogenic and oncogenic herpesvirus of chickens, can antagonize host innate immune responses to achieve persistent infection. With a functional screen, we identified five MDV proteins that blocked beta interferon (IFN-β) induction downstream of the cGAS-STING pathway. Specifically, the MDV major oncoprotein Meq impeded the recruitment of TANK-binding kinase 1 and IFN regulatory factor 7 (IRF7) to the STING complex, thereby inhibiting IRF7 activation and IFN-β induction. Meq overexpression markedly reduced antiviral responses stimulated by cytosolic DNA, whereas knockdown of Meq heightened MDV-triggered induction of IFN-β and downstream antiviral genes. Moreover, Meq-deficient MDV induced more IFN-β production than wild-type MDV. Meq-deficient MDV also triggered a more robust CD8+ T cell response than wild-type MDV. As such, the Meq-deficient MDV was highly attenuated in replication and lymphoma induction compared to wild-type MDV. Taken together, these results revealed that MDV evades the cGAS-STING DNA sensing pathway, which underpins the efficient replication and oncogenesis. These findings improve our understanding of the virus-host interaction in MDV-induced lymphoma and may contribute to the development of novel vaccines against MDV infection.

Marek's Disease Virus-Encoded MicroRNA 155 Ortholog Critical for the Induction of Lymphomas Is Not Essential for the Proliferation of Transformed Cell Lines.

MicroRNAs (miRNAs) are small noncoding RNAs with profound regulatory roles in many areas of biology, including cancer. MicroRNA 155 (miR-155), one of the extensively studied multifunctional miRNAs, is important in several human malignancies such as diffuse large B cell lymphoma and chronic lymphocytic leukemia. Moreover, miR-155 orthologs KSHV-miR-K12-11 and MDV-miR-M4, encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) and Marek's disease virus (MDV), respectively, are also involved in oncogenesis. In MDV-induced T-cell lymphomas and in lymphoblastoid cell lines derived from them, MDV-miR-M4 is highly expressed. Using excellent disease models of infection in natural avian hosts, we showed previously that MDV-miR-M4 is critical for the induction of T-cell lymphomas as mutant viruses with precise deletions were significantly compromised in their oncogenicity. However, those studies did not elucidate whether continued expression of MDV-miR-M4 is essential for maintaining the transformed phenotype of tumor cells. Here using an in situ CRISPR/Cas9 editing approach, we deleted MDV-miR-M4 from the MDV-induced lymphoma-derived lymphoblastoid cell line MDCC-HP8. Precise deletion of MDV-miR-M4 was confirmed by PCR, sequencing, quantitative reverse transcription-PCR (qRT-PCR), and functional analysis. Continued proliferation of the MDV-miR-M4-deleted cell lines demonstrated that MDV-miR-M4 expression is not essential for maintaining the transformed phenotype, despite its initial critical role in the induction of lymphomas. Ability to examine the direct role of oncogenic miRNAs in situ in tumor cell lines is valuable in delineating distinct determinants and pathways associated with the induction or maintenance of transformation in cancer cells and will also contribute significantly to gaining further insights into the biology of oncogenic herpesviruses.IMPORTANCE Marek's disease virus (MDV) is an alphaherpesvirus associated with Marek's disease (MD), a highly contagious neoplastic disease of chickens. MD serves as an excellent model for studying virus-induced T-cell lymphomas in the natural chicken hosts. Among the limited set of genes associated with MD oncogenicity, MDV-miR-M4, a highly expressed viral ortholog of the oncogenic miR-155, has received extensive attention due to its direct role in the induction of lymphomas. Using a targeted CRISPR-Cas9-based gene editing approach in MDV-transformed lymphoblastoid cell lines, we show that MDV-miR-M4, despite its critical role in the induction of tumors, is not essential for maintaining the transformed phenotype and continuous proliferation. As far as we know, this was the first study in which precise editing of an oncogenic miRNA was carried out in situ in MD lymphoma-derived cell lines to demonstrate that it is not essential in maintaining the transformed phenotype.

Multifunctional miR-155 Pathway in Avian Oncogenic Virus-Induced Neoplastic Diseases.

MicroRNAs (miRNAs) are small noncoding RNAs that fine-tune the responses of the cell by modulating the cell transcriptome and gene expression. MicroRNA 155 (miR-155) is a conserved multifunctional miRNA involved in multiple roles including the modulation of the immune responses. When deregulated, miR-155 can also contribute to cancer as has been demonstrated in several human malignancies such as diffuse large B cell lymphoma, chronic lymphocytic leukemia, as well as in Epstein–Barr virus (EBV)-induced B cell transformation. Avian oncogenic viruses such as Marek’s disease virus (MDV), avian leukosis virus (ALV), and reticuloendotheliosis virus (REV) that account for more than 90% of cancers in avian species, also make use of the miR-155 pathway during oncogenesis. While oncogenic retroviruses, such as ALV, activate miR-155 by insertional activation, acutely transforming retroviruses use transduced oncogenes such as v-rel to upregulate miR-155 expression. MDV on the other hand, encodes a functional miR-155 ortholog mdv1-miR-M4, similar to the miR-155 ortholog kshv-miR-K11 present in Kaposi’s sarcoma-associated herpesvirus (KSHV). We have shown that mdv1-miR-M4 is critical for the induction of MDV-induced lymphomas further demonstrating the oncogenic potential of miR-155 pathway in cancers irrespective of the diverse etiology. In this review, we discuss on our current understanding of miR-155 function in virus-induced lymphomas focusing primarily on avian oncogenic viruses.

Mutational landscape of T-cell lymphoma in mice lacking the DNA mismatch repair gene Mlh1: no synergism with ionizing radiation.

Biallelic germline mutations in the DNA mismatch repair gene MLH1 lead to constitutional mismatch repair-deficiency syndrome and an increased risk for childhood hematopoietic malignancies, including lymphoma and leukemia. To examine how Mlh1 dysfunction promotes lymphoma as well as the influence of ionizing radiation (IR) exposure, we used an Mlh1-/- mouse model and whole-exome sequencing to assess genomic alterations in 23 T-cell lymphomas, including 8 spontaneous and 15 IR-associated lymphomas. Exposure to IR accelerated T-cell lymphoma induction in the Mlh1-/- mice, and whole-exome sequencing revealed that IR exposure neither increased the number of mutations nor altered the mutation spectrum of the lymphomas. Frequent mutations were evident in genes encoding transcription factors (e.g. Ikzf1, Trp53, Bcl11b), epigenetic regulators (e.g. Suv420h1, Ep300, Kmt2d), transporters (e.g. Rangap1, Kcnj16), extracellular matrix (e.g. Megf6, Lrig1), cell motility (e.g. Argef19, Dnah17), protein kinase cascade (e.g. Ptpro, Marcks) and in genes involved in NOTCH (e.g. Notch1), and PI3K/AKT (e.g. Pten, Akt2) signaling pathways in both spontaneous and IR-associated lymphomas. Frameshift mutations in mononucleotide repeat sequences within the genes Trp53, Ep300, Kmt2d, Notch1, Pten and Marcks were newly identified in the lymphomas. The lymphomas also exhibited a few chromosomal abnormalities. The results establish a landscape of genomic alterations in spontaneous and IR-associated lymphomas that occur in the context of mismatch repair dysfunction and suggest potential targets for cancer treatment.

Kinetics of cytokine mRNA and protein expression by plastic adherent cells in the thymus after split-dose irradiation

Whole body irradiation causes significant apoptosis in various tissues such as the thymus. If apoptotic cells outnumber the phagocytic capacity of macrophages, apoptosis becomes secondary necrosis, inducing inflammatory cytokine expression in macrophages. Radiation also induces thymic lymphomas in C57BL/6 mice after four consecutive irradiations with 1.6 Gy X-rays with nearly 100% incidence. Since cancer development is modulated by a microenvironment involving macrophages, we examined the kinetics of thymocyte number and plastic adherent cell number in the thymus as well as cytokine mRNA expression by plastic adherent cells in the thymus after split-dose irradiation. Upon split-dose irradiation, thymocyte number changed dramatically, whereas plastic adherent cell number did not. Among cytokine mRNAs tested, IL-1β, IL-11 and IL-12p40 mRNAs were up regulated 2 days after the 1st and 2nd, 3rd and 4th, and 2nd and 3rd irradiations, respectively. On the other hand, TNF-α mRNA was up regulated 2 days after the 3rd irradiation and 2 weeks after the 4th irradiation. The level of IL-11 protein was also increased 2 days after 3rd and 4th irradiations. These results suggest that, upon split-dose irradiation, macrophages in the thymus produce various cytokines in a time-dependent manner, thereby contributing to induction of thymic lymphomas.

Modulating SIRT1 activity variously affects thymic lymphoma development in mice

SIRT1 is a protein deacetylase with a broad range of biological functions, many of which are known to be important in carcinogenesis, however much of the literature regarding the role of SIRT1 in cancer remains conflicting. In this study we assessed the effect of SIRT1 on the initiation and progression of thymic T cell lymphomas. We employed mouse strains in which SIRT1 activity was absent or could be reversibly modulated in conjunction with thymic lymphoma induction using either the N-nitroso-N-methylurea (NMU) carcinogenesis or the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) transgene. Decreased SIRT1 activity reduced the development of thymic lymphomas in the NMU-treated mice but was permissive for the formation of lung adenomas. Conversely, in the NPM-ALK transgenic mice, decreased SIRT1 activity had a modest promoting effect in the development of thymic lymphomas. The results of the work presented here add to the growing body of evidence that sirt1 is neither an outright oncogene nor a tumor suppressor. These opposing results in two models of the same disease suggest that the influence of sirt1 on carcinogenesis may lie in a role in tumor surveillance.

A clonotype-independent pre-TCR complex and its downstream signals can support transformation of thymic T cells.

Abstract The kinase ataxia telangiectasia mutated (ATM) communicates between molecules that sense DNA damage in the form of double stranded breaks (DSB) and effector mechanisms that maintain genomic integrity. Persistent DSBs can lead to transformation and ATM-deficiency is associated with increased lymphoid malignancies in both humans and mice. ATM-deficient mice exclusively develop thymic T cell lymphomas with high penetrance. We explored the requirement for specific components of the TCR and its signaling pathway for the induction of these thymic lymphomas. We generated multiple strains of ATM-deficient mice in which mature T cell are absent by deletion of CD3ɛ, an invariant component of the pre-TCR complex; by deletion of RAG or TCRβ, in which recombining TCR variable components are deleted; or by deletion of LAT, an important component of pre-TCR and TCR signaling. These strains all showed a similar and severe developmental arrest at thymic DN3. Despite this arrest, mice deficient in RAG or TCRβ, exclusively developed thymic T cell lymphomas. In contrast, mice deficient in CD3ɛ or LAT, developed no or few T cell tumors, respectively, but developed B cell lymphomas. These findings suggest the importance of a clonotype-independent TCR complex and its downstream signals in transformation of T cells. Experiments are in progress to ask if survival of ATMKO T cell lymphomas after transformation is similarly dependent on CD3ɛ and LAT signaling.

Prognostic role of the neutrophil-to-lymphocyte ratio in patients with primary central nervous system lymphoma.

Neutrophil-to-lymphocyte ratio (NLR) is one of the parameters of a complete blood cell count (CBC) test and has been reported to be an easily accessible prognostic marker in aggressive cancer, including non-Hodgkin lymphoma (NHL). Primary central nervous system lymphoma (PCNSL) is an extranodal NHL with highly aggressive features. However, the importance of the NLR has never been assessed in PCNSL. This retrospective study enrolled 62 biopsy-proven patients whose baseline NLR was available, and reviewed their medical records to compare both high (≥2.0) and low NLR (<2.0) groups, in terms of clinical characteristics and outcomes. The low NLR group showed significantly better response rates to induction chemotherapy compared to the high NLR group (p=0.041). At a median follow-up of 41.5 months, the high NLR group revealed a significantly worse 3-year overall survival (OS) (42.5 vs. 71.2%; p=0.031) and a worse 3-year progression-free survival (PFS) (37.3 vs. 60.1%; p=0.028). Univariable Cox analysis results showed that a high NLR at diagnosis was a poor prognostic factor for both 3-year OS (HR 2.64, 95% CI 1.06-6.60; p=0.038) and 3-year PFS (HR 2.41, 95% CI 1.07-5.42; p=0.034). However, multivariable analyses adjusting for International Extranodal Lymphoma Study Group (IELSG) score and induction chemotherapy regimen with rituximab, which were strongly prognostic in this study, showed no statistical significance even with the high NLR group’s tendency towards a worse 3-year OS (HR 2.36, 95% CI 0.84-6.62, p=0.102) and a worse 3-year PFS (HR 2.28, 95% CI 0.93-5.63, p=0.073). In conclusion, given that NLR is simple and easily obtainable, it might play a potentially prognostic role in PCNSL from early disease onset.

Clinical Features and Outcomes of 24 Cases of Blastic Plasmacytoid Dendritic Cell Neoplasm-Single Institutional Experience

Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive hematopoietic malignancy originating from precursor plasmacytoid dendritic cells. Clinically, patients usually present with skin lesions and simultaneous involvement of peripheral blood, bone marrow, lymph node, spleen and central nervous system. Median survival from diagnosis has been reported to range from 9 to 12 months (Julia F et al. Br J Dermatol. 2013;579-86). The optimal treatment for BPDCN has not been established yet. Majority of patients demonstrate response to lymphoma or acute lymphoblastic leukemia-like chemotherapy induction regimens. A consolidation with autologous or allogeneic hematopoietic stem cell transplantation may improve outcome of selected patients. Limited data are available regarding prognostic and predictive factors. In this study we analyzed clinical and laboratory characteristics and assessed their impact on clinical outcome.Methods and Materials: Patients with diagnosis of BPDCN at Moffitt Cancer Center between 2000 and 2015 were retrieved from a clinical database. The diagnosis was confirmed by morphology, laboratory data, and immunopehnotying, according to 2008 WHO Classification of Hematopoietic Neoplasms. The relevant clinicopathologic features extracted from electronic medical records were recorded. Treatment modalities and responses to therapy were correlated with clinical outcomes. A univariate linear discriminant analysis was used for risk stratification. Overall survival was analyzed by Kaplan-Meier method.Results: We identified 24 patients with a median age of 74 years (range: 36-94 years) and a male:female ratio of 23:1. Mean hemoglobin was 11.83 2.48 g/dL; mean platelet count was 134 ± 84 k/µL; and mean white blood count was 6.34 ± 7.25 k/µL. Only one patient had an Eastern Cooperative Oncology Group (ECOG) performance status greater than 2. Four patients demonstrated skin lesions only. Twenty patients (83.3%) demonstrated extracutaneous or systemic involvements. Peripheral blood, bone marrow, lymph node, spleen and cerebrospinal fluid (CSF) involvements were found in 11 (45.8%), 16 (66.7%), 8(33.3%), and 4(17%) patients, respectively. Six of 20 (30%) patients with systemic involvement were treated with CHOP. Two of 6 patients were treated with hyper-CVAD followed by an allogeneic hematopoietic stem cell transplant. Autologous transplant was administered to one patient who was treated with both CHOP and ICE induction regimens. Median overall survival (OS) of the cohort was 49.9 months (95% CI, 19.9 - 81 months) and median follow up duration was 33.5 months (95% CI, 3-147 months). Statistical analysis showed the following parameters were not prognostic predictors of OS at diagnosis: hemoglobin level (<10 g/dL), leukocytosis (>11,000/ul), thrombocytopenia (<100,000/ul), age >60, peripheral blood and bone marrow involvement (p=0.51, p=0.278, p=0.684, p=0.9288, p=0.2074, and p=0.8633, respectively). Lymph node involvement at diagnosis was associated with a shorter OS compared to those without lymph node involvement (p=0.0305). CHOP versus more aggressive chemotherapies did not show difference in OS (p=0.8939). Bone marrow transplant (1 autologous and 2 allogeneic) showed a trend to have longer OS (86 versus 64 months; p=0.12).Conclusion: BPDCN has an aggressive biological behavior. Median overall survival of 49.9 months observed in our study compares favorably with OS of 12 months in previous reports. Lymph node involvement at diagnosis may have adverse impact on clinical outcomes. Larger scale studies are needed to identify risk factors that may have impact on outcomes and to establish standardized therapy in patients with BPDCN. DisclosuresSokol:Seatle Genetics: Research Funding; Spectrum: Consultancy; Celgene: Consultancy.

Addition of a UL5 helicase-primase subunit point mutation eliminates bursal–thymic atrophy of Marek's disease virus ∆Meq recombinant virus but reduces vaccinal protection

Marek's disease virus (MDV) is an oncogenic alphaherpesvirus and the causative agent of Marek's disease (MD), characterized by immunosuppression, paralysis, nerve enlargement and induction of T-cell lymphomas in chickens. Despite widespread usage of vaccines since the 1970s to control MD, more virulent field strains of MDV have emerged that overcome vaccinal protection, necessitating the development of new and more protective MD vaccines. The ∆Meq virus, a recombinant Md5 strain MDV lacking the viral oncogene Meq, is one candidate MD vaccine with great potential but unfortunately it also causes bursal–thymic atrophy (BTA) in maternal antibody negative chickens, raising concerns that impede commercial use as a vaccine. Previously, we identified a point mutation within UL5 that reduced in vivo replication in attenuated viruses. We proposed that introduction of the UL5 point mutation into the ∆Meq virus would reduce in vivo replication and eliminate BTA yet potentially retain high protective abilities. In birds, the ∆Meq+UL5 recombinant MDV had reduced replication compared to the original ∆Meq virus, while weights of lymphoid organs indicated that ∆Meq+UL5 did not induce BTA, supporting the hypothesis that reduction of in vivo replication would also abolish BTA. Vaccine trials of the ∆Meq+UL5 virus compared to other ∆Meq-based viruses and commercial vaccines show that, while the ∆Meq+UL5 does provide vaccinal protection, this protection was also reduced compared to the original ∆Meq virus. Therefore, it appears that a very delicate balance is required between levels of replication able to induce high vaccinal protection, yet not so high as to induce BTA.

The significance of the individual Meq-clustered miRNAs of Marek's disease virus in oncogenesis.

Marek's disease virus (MDV) is an important oncogenic alphaherpesvirus that induces rapid-onset T-cell lymphomas in its natural hosts. The Meq-clustered miRNAs encoded by MDV have been suggested to play potentially critical roles in the induction of lymphomas. Using the technique of bacterial artificial chromosome mutagenesis, we have presently constructed a series of specific miRNA-deleted mutants and demonstrate that these miRNAs are not essential for replication of MDV and have no effects on the early cytolytic or latent phases of the developing disease. However, compared to the parental GX0101, mortality of birds infected with the mutants GXΔmiR-M2, GXΔmiR-M3, GXΔmiR-M5, GXΔmiR-M9 and GXΔmiR-M12 was reduced from 100 % to 18 %, 30 %, 48 %, 24 % and 14 %, coupled with gross tumour incidence reduction from 28 % to 8 %, 4 %, 12 %, 8 % and 0 %, respectively. Our data confirm that except for mdv1-miR-M4, the other Meq-clustered miRNAs also play critical roles in MDV oncogenesis. Further work will be needed to elucidate the miRNA-mediated regulatory mechanisms that trigger the development of MD lymphomas.