Acute myeloid leukemia (AML) is a very heterogeneous disease associated with cytogenetic aberrations and genetic mutations. Many of these changes have been revealed and their detection became usual part of the diagnostic process today. However, changes of expression profiles of small, noncoding RNAs, so called microRNAs (miRNAs), are less known and not used for diagnostics yet. These RNAs, 19-24 nucleotides long, take part in the regulation of expression of different genes through complementary base pairing to the 3'non- translated region (3'UTR) of the target messenger RNA (mRNA). They can influence key processes of the cell, like differentiation, proliferation or apoptosis. The changes in expression of different miRNAs are known from different types of cancers. In solid tumors, they are usually detected from bioptic samples; but also plasma samples are now in the center of attention as so called liquid biopsies providing the information about molecular genetic events in the organism. Many studies have revealed deregulated miRNAs in the bone marrow, full blood or isolated progenitor cells (CD34+) of AML patients, only four of them have analyzed plasma samples. We focused on the plasma samples and we targeted on such miRNAs, which levels differ at AML diagnosis and after the chemotherapy. Out of...

Acute myeloid leukemia (AML) develops following oncogenic alterations to hematopoietic stem (HSC) and progenitor cells (HSPCs) in the bone marrow, resulting in dysregulated proliferation of immature myeloid progenitors that interferes with normal hematopoiesis. Understanding the mechanisms of HSPC protection against damage and excessive division, and how these pathways are altered during leukemic progression, is vital for establishing effective therapies. Here, we show that autophagy, a lysosomal degradation pathway, is increased in HSPCs using a novel imaging flow cytometry autophagy assay. Loss of hematopoietic autophagy following deletion of key gene Atg5 resulted in increased HSC proliferation, leading to HSC exhaustion and bone marrow failure. Although erythrocyte and lymphocyte populations were negatively impacted by autophagy loss, myeloid cells showing immature characteristics were expanded. Deletion of Atg5 in an AML model resulted in increased proliferation under metabolic stress, dependent on the glycolytic pathway, and aberrant upstream mTOR signaling. Moreover, modulation of Atg5 altered leukemic response to culture with stromal cells. Finally, primary AML cells displayed multiple markers of decreased autophagy. These data suggest a role for autophagy in preserving HSC function, partially through suppression of HSPC proliferation, and indicate that decreased autophagy may benefit AML cells. We postulate that modulation of autophagy could help maintain stem cell function, for example during transplantation, and aid AML therapy in a setting-specific manner.

Acute myeloid leukemia (AML) the most common acute leukemia in adults is characterized by various cytogenetic and molecular abnormalities. However, the genetic etiology of the disease is not yet fully understood. MicroRNAs (miRNAs) are small single- stranded noncoding RNAs that are negative regulators of gene expression. miRNAs influence processes of proliferation, differentiation and apoptosis. Deregulation of miRNAs expression can contribute to human disease. Circulating miRNAs are emerging biomarkers in many diseases and cancers such as breast cancer, colorectal cancer and lung cancer. However, defining a plasma miRNA signature in AML that could serve as a biomarker for diagnosis has been conducted only once. We studied miRNA expression in plasma of 8 AML patients in first detection of the disease and repeatedly after achieving remission using TaqMan miRNA microarray for 750 human miRNA. The plasma expression level of 25 miRNA was down-regulated whilst that of 20 miRNA was up-regulated in the AML group at diagnosis when compared to healthy controls. The plasma expression level of 21 miRNA was down-regulated whilst that of 13 miRNA was up-regulated in the AML group in remission compared to healthy controls. Keywords acute myeloid leukemia (AML), biomarker, microRNA (miRNA), plasma, TaqMan Low...

Adoptive immunotherapy using chimeric antigen receptor (CAR)-modified T cells targeting CD19 has shown remarkable therapeutic efficacy against B cell leukemia and lymphoma, and provided proof of concept for therapeutic potential in other hematologic malignancies. Acute myeloid leukemia (AML) is an entity with an unmet medical need for effective and curative treatments. Therefore, there is a strong desire for development of potentially curative CAR-T cell immunotherapy for AML treatment. FMS-like tyrosine kinase 3 (FLT3) is a homodimeric transmembrane protein expressed uniformly by AML blasts. FLT3 plays a vital role in the survival of AML blasts and is a key driver of leukemia-genesis in AML cases with internal tandem duplication (FLT3ITD) and tyrosine kinase domain (TKD) mutations. These attributes suggest that FLT3 could be an excellent target for CAR-T cell immunotherapy. Here, we engineered human CD4+ and CD8+ T cells to express FLT3-specific CARs and demonstrate that they confer potent reactivity against AML cell lines and primary AML blasts that express either wild-type FLT3 or FLT3-ITD. Further, we show that FLT3 CAR-T cells exert potent antileukemia activity in xenograft models of AML and induce complete remissions. We also demonstrate that FLT3-expression on FLT3-ITD+ AML cells can be augmented by FLT3 inhibitors, which lead to increased recognition by CARs and improved efficacy of FLT3 CAR-T cells. We confirmed this principle with three different FLT3 inhibitors which are at distinct stages of clinical development i.e. Phase II/III clinical trial (crenolanib, quizartinib) and clinically approved (midostaurin). Further, we observed the strongest anti-leukemia activity of FLT3 CAR-T cells in combination with crenolanib in vivo. FLT3 is known to be expressed by normal hematopoietic stem and progenitor cells. We evaluated FLT3-expression on normal hematopoietic stem cells (HSCs) using flow cytometry and confirmed lower level of FLT3-expression on HSCs and progenitors compared to AML cells. As anticipated, we found that FLT3 CAR-T cells recognize normal HSCs in vitro and in vivo, and compromise normal hematopoiesis, suggesting that adoptive therapy with FLT3 CAR-T cells will require successive CAR-T cell depletion and allogeneic HSC transplantation (HSCT) to reconstitute the hematopoietic system. Moreover, an FLT3 inhibitor treatment does not increase FLT3-expression on HSCs. Accordingly, we demonstrate that the depletion of FLT3 CAR-T cells is possible with inducible Caspase 9 (iCasp9) safety switch. Collectively, our data establish FLT3 as a novel CAR target in AML with particular relevance in high-risk FLT3-ITD+ AML. Our data demonstrate that FLT3 CAR-T cells act synergistically with FLT3 inhibitors in FLT3-ITD+ AML. i.e. FLT3 inhibitors-induced upregulation of FLT3 in FLT3-ITD+ AML cells enhances their recognition and elimination by FLT3 CAR-T cells. Due to recognition of normal HSCs, the clinical use of FLT3 CART cells is likely restricted to a defined therapeutic window and must be followed by CART cell depletion and allogeneic HSCT for hematopoietic reconstitution. The data provide rational to use FLT3 CAR-T cells in combination with FLT3 inhibitors to augment the anti-leukemia efficacy of FLT3 CAR-T cells in high-risk FLT3-ITD+ AML patients, and to mitigate the risk of relapse with FLT3-negative AML variants, which could otherwise develop under therapeutic pressure. The data provide proof of concept for synergistic use of CAR-T cell immunotherapy and small molecule targeted therapy and encourage the clinical evaluation of this combination treatment in high-risk patients with FLT3-ITD+ AML. / Adoptive Immuntherapie, die Chimäre- Antigenrezeptor (CAR) –modifizierte, gegen CD19 gerichtet T-Zellen verwendet, hat eine bemerkenswerte therapeutische Wirksamkeit gegen B-Zell-Leukämien und -Lymphome und großes therapeutisches Potenzial für die Behandlung anderer hämatologischer Erkrankungen gezeigt. Die Akute Myeloische Leukämie (AML) ist hierbei eine Entität, für die es bisher an wirksamen und kurativen Therapien fehlt und für die die Entwicklung einer potentiell kurativen CAR-T-Zellimmuntherapie von großer Bedeutung ist. FMS-like tyrosine kinase 3 (FLT3) ist ein homodimeres Transmembranprotein, das von AML-Blasten uniform exprimiert wird. FLT3 spielt eine wichtige Rolle beim Überleben von AML-Blasten und ist ein Schlüsselfaktor in der Leukämie-Genese bei AML-Fällen mit interner Tandem-Duplikation (FLT3-ITD) und Tyrosinkinase-Domänen (TKD)-Mutationen. Diese Eigenschaften legen die Vermutung nahe, dass FLT3 ein ausgezeichnetes Target für die CAR-T-Zell-Immuntherapie darstellen könnte. Daher setzten wir dort an und modifizierten humane CD4+ und CD8+ T-Zellen, um FLT3-spezifische CARs zu exprimieren, und konnten nachweisen, dass diese eine starke Reaktivität gegen AML-Zelllinien und primäre AML-Blasten besitzen, die entweder den FLT3-Wildtyp oder FLT3-ITD exprimieren. Weiterhin konnten wir zeigen, dass FLT3 CAR-T-Zellen in AML-Xenograft-Modellen eine starke anti-Leukämie-Aktivität besitzen und vollständige Remissionen hervorrufen können. Zudem gelang der Nachweis, dass die FLT3-Expression auf FLT3-ITD+ AML-Zellen durch FLT3-Inhibitoren verstärkt werden kann, was zu einer erhöhten Erkennung durch die CARs und einer verbesserten Wirksamkeit von FLT3-CAR-T-Zellen führt. Wir konnten dieses Prinzip mit drei verschiedenen FLT3-Inhibitoren belegen, die sich in unterschiedlichen Stadien der klinischen Entwicklung befinden, d. h. aus einer Klinischen Phase II / III-Studie (Crenolanib, Quizartinib) und einem klinisch zugelassenen Inhibitor (Midostaurin). Darüber hinaus beobachteten wir die stärkste anti-Leukämie-Aktivität von FLT3 CAR-T-Zellen in einer Kombination mit Crenolanib in vivo. Es ist bekannt, dass FLT3 von normalen hämatopoetischen Stamm- und Vorläuferzellen exprimiert wird. Wir untersuchten die FLT3-Expression in normalen hämatopoetischen Stammzellen (HSCs) mittels Durchflusszytometrie und bestätigten im Vergleich zu AML-Zellen eine niedrigere FLT3-Expression auf HSCs und Vorläuferzellen. Wie erwartet, zeigte sich, dass FLT3 CAR-T-Zellen normale HSCs in vitro und in vivo erkennen und die normale Hämatopoese beeinträchtigen, was darauf hindeutet, dass eine adoptive Therapie mit FLT3 CAR-T-Zellen eine sukzessive CAR-T-Zell-Depletion und allogene HSC-Transplantation erfordert, um das hämatopoetische System wiederaufzubauen. Darüber hinaus erhöht die Behandlung mit einem FLT3-Inhibitor nicht die FLT3-Expression auf den HSCs. Dementsprechend konnten wir aufzeigen, dass die Depletion von FLT3 CAR-T Zellen mit einer induzierbaren Caspase 9 (iCasp9) als „Sicherheitsschalter“ möglich ist. Zusammenfassend etablieren unsere Daten FLT3 als ein neuartiges CAR-Target in der Behandlung von AML mit besonderer Relevanz für die Hochrisiko-FLT3-ITD+ AML. Unsere Daten zeigen, dass FLT3 CAR-T-Zellen synergistisch mit FLT3-Inhibitoren in FLT3-ITD+ AML wirken, d.h. eine FLT3-Inhibitoren-induzierte Hochregulation von FLT3 in FLT3-ITD+ AML-Zellen bewirkt und dies die Erkennung und Eliminierung durch FLT3-CAR-T-Zellen verstärkt. Durch ihre Eigenschaft der Erkennung von normalen HSCs ist die klinische Verwendung von FLT3 CAR-T-Zellen wahrscheinlich auf ein definiertes therapeutisches Fenster beschränkt und muss durch eine anschließende CAR-T-Zell-Depletion und eine allogene HSCT zur Rekonstitution des hämatopoetischen Systems ergänzt werden. In Anbetracht der Daten scheint es sinnvoll, FLT3-CAR-T-Zellen in Kombination mit FLT3-Inhibitoren zu verwenden, um die anti-leukämische Wirksamkeit von FLT3-CAR-T-Zellen bei Hochrisiko-FLT3-ITD+ AML-Patienten zu erhöhen und das Risiko eines Rückfalls mit FLT3-negativen AML-Varianten zu verringern, die sich sonst therapiebedingt entwickeln könnten. Die Daten stellen ein Proof-of-Concept für den synergistischen Einsatz von CAR-T-Zell-Immuntherapie und niedermolekularen Inhibitoren dar, der eine klinische Evaluation dieser Kombinationsbehandlung bei Hochrisikopatienten mit FLT3-ITD+ AML erstrebenswert macht.

Η θεραπεία της Οξείας Μυελογενούς Λευχαιμίας (ΟΜΛ) είναι συχνά ανεπιτυχής λόγω ανάπτυξης κυτταρικής αντίστασης στα αντιλευχαιμικά φάρμακα. Εκτός από την έκφραση Ρ-γλυκοπρωτείνης στα λευχαιμικά κύτταρα, άλλοι κυτταρικοί παράγοντες μπορούν επίσης να συμβάλλουν στην χημειοαντίσταση. Η c- Jun N-terminal Kinase (JNK) είναι μία πρωτεινική κινάση που ενεργοποιείται όταν τα κύτταρα εκτεθούν σε χημειοθεραπευτικά φάρμακα (ΧΜΘ). Πρόσφατες μελέτες σε συμπαγείς όγκους συσχετίζουν την χημειοαντίσταση με αδυναμία των καρκινικών κυττάρων να ενεργοποιήσουν τη JNK κατόπιν επίδρασης ΧΜΘ. Σκοπός της εργασίας είναι να διερευνήσει αν η χημειοαντίσταση στην ΟΜΛ οφείλεται σε ενδογενή αδυναμία των λευχαιμικών βλαστών να ενεργοποιήσουν τη JNK. Μεθοδολογία: Συγκρίναμε ευαίσθητες (U937) και ανθεκτικές (U937R) στις ανθρακυκλίνες κυτταρικές σειρές ΟΜΛ ως προς την δυνατότητα in vitro ενεργοποίησης της JNK κατόπιν επίδρασης ΧΜΘ (Western Blot). Επιπλέον, στις λευχαιμικές κυτταρικές σειρές ελέγξαμε απευθείας τη σημασία της JNK στην χημειοαντίσταση με πειράματα α) αποσιώπησης της JNK με JNK1–στοχεύον siRNA και β) ενεργοποίησης της JNK (διαμόλυνση με τον ΜΚΚ4/SEK1 άνωθεν ενεργοποιητή της JNK) Περαιτέρω, ελέγξαμε την in vitro δυνατότητα ενεργοποίησης της JNK σε 29 πρωτογενή μυελικά δείγματα ΟΜΛ κατόπιν βραχείας διάρκειας (30-60min) έκθεση στην daunorubicin (1μΜ) και συσχετίσαμε τα εργαστηριακά δεδομένα με κλινικά χαρακτηριστικά των ασθενών με ΟΜΛ. Αποτελέσματα: In vitro θεραπεία των U937 κυττάρων με ανθρακυκλίνες προκάλεσε ισχυρή και ταχεία ενεργοποίηση της JNK και απόπτωση. Αντίθετα, στα πολυανθεκτικά U937R κύτταρα δεν παρατηρήθηκε ενεργοποίηση της JNK, ακόμη και σε συνθήκες υψηλής ενδοκυττάριας συγκέντρωσης ανθρακυκλινών. Αποσιώπηση της JNK στα ευαίσθητα U937 κύτταρα τα έκανε ανθεκτικά στις ανθρακυκλίνες (JNK1-siRNA διαμολυσμένα U937 κύτταρα εμφάνισαν 50.4% και 61.3% ελαττωμένη daunorubicin- (DNR, 1μΜ 24hr) και doxorubicin- (DOX, 1.5μΜ 24hr) προκαλούμενη απόπτωση αντίστοιχα, συγκριτικά με U937 κύτταρα-μάρτυρες, P<0.001). Αντίστροφα, εκλεκτική ενεργοποίηση της ανενεργού JNK στα ανθεκτικά U937R κύτταρα τα έκανε 3.3 φορές πιο ευαίσθητα στη DNR και 3.1 φορά πιο ευαίσθητα στη DΟΧ, συγκριτικά με U937R κύτταρα-μάρτυρες. Επιπρόσθετα, παρατηρήσαμε ισχυρή συσχέτιση μεταξύ των in vitro φαρμακοδυναμικών αλλαγών των επιπέδων ενεργοποίησης της JNK στους λευχαιμικούς βλάστες και της ανταπόκρισης των ασθενών με ΟΜΛ στη χημειοθεραπευτική αγωγή (P=0.012). Η απουσία ενεργοποίησης της JNK στα βλαστικά κύτταρα συσχετίστηκε επίσης με αρνητικούς προγνωστικούς παράγοντες για την ΟΜΛ, όπως γηραιότερη ηλικία των ασθενών (P=0.046) και ΟΜΛ αναπτυσσόμενη επί εδάφους μυελοδυσπλασίας (P=0.017). Συνοψίζοντας, τα in vitro και in vivo αποτελέσματα μας προτείνουν την ενδογενή αποτυχία ενεργοποίησης της πρωτεινικής κινάσης JNK στους λευχαιμικούς βλάστες σαν έναν εναλλακτικό μηχανισμό χημειοαντίστασης στην ΟΜΛ. Η διελεύκανση των μηχανισμών εκείνων που επιφέρουν καταστολή της JNK στην χημειοανθεκτική ΟΜΛ μπορεί να ωφελήσει θεραπευτικά. / Chemotherapy resistance is a major challenge in acute myeloid leukemia (AML). Besides the P-glycoprotein efflux, additional cellular factors may contribute to drug-resistance in AML. c- Jun N-terminal Kinase (JNK) is activated after exposure of cells to chemotherapeutics. We asked whether chemoresistance in AML is attributed to intrinsic failure of the AML blasts to activate JNK. In vitro treatment of U937 AML cell line with anthracyclines induced a rapid and robust JNK phosphorylation and apoptosis. In contrast, the anthracyline-resistant derivative cell lines U937R and URD40 showed no JNK activation after exposure to anthracyclines, also at doses that resulted in high accumulation of the drug within the cells. RNA interference-based depletion of JNK1 in drug-sensitive U937 cells made them chemoresistant, whereas selective restoration of the inactive JNK pathway in the resistant U937R cells sensitized them to anthracyclines. Short-term in vitro exposure of primary AML cells (n=29) to daunorubicin showed a strong correlation between the in vitro pharmacodymanic changes of phospho-JNK levels and the response of patients to standard induction chemotherapy (P=0.012). We conclude that JNK activation failure confers another mechanism of anthracycline resistance in AML. Elucidating the ultimate mechanisms leading to JNK suppression in chemoresistant AML may be of major therapeutic value.

Le CD81 est une molécule de surface appartenant à la superfamille des tetraspanines. Son rôle pronostique a été précédemment étudié dans les pathologies lymphoïdes, dont le myélome multiple où son expression est associée à un pronostic péjoratif. A ce jour, ce marqueur n'a pas été étudié dans les leucémies aiguës myéloïdes (LAM). Nous avons étudié l'expression membranaire du CD81 sur les blastes de LAM au diagnostic, son association aux autres caractéristiques des LAM et sa potentielle influence sur la survie des patients sur une cohorte de 134 patients traités par chimiothérapie intensive.Le CD81 a été retrouvé chez 92 patients sur 134 (69%). Les patients exprimant ce marqueur avaient une leucocytose initiale plus élevée (p=0.02) et présentaient une cytogénétique intermédiaire ou défavorable (p<0.001). L'expression du CD81 avait un impact négatif sur la survie des patients (survie sans évènements (EFS), survie globale (OS), survie sans rechute (RFS)) en analyse uni- (p<0.001) et multivariées (p=0.003, 0.002 and <0.001 respectivement).De plus, le CD81 avait un impact négatif sur l'OS des patients avec une mutation de NPM1 (p=0.01) et chez les patients du groupe cytogénétique favorable (p=0.002) selon la classification ELN.Les anomalies du cycle cellulaire étant associées à la chimiorésistance, la croissance tumorale et l'agressivité de la pathologie, nous avons étudié l'expression du Ki67 sur les blastes de LAM au diagnostic. Ainsi, 10 prélèvements médullaires de patients avec une faible expression du CD81 par les blastes (moins de 20% de positivité) et 10 prélèvements avec une forte expression du marqueur ont été étudiés. Nous avons pu démontrer une expression significativement inférieure du Ki67 sur les blastes CD81 positifs par rapport aux blastes CD81 négatifs (p<0.001), suggérant ainsi un rôle potentiel du CD81 dans le contrôle du cycle cellulaire. De plus, nous nous sommes intéressés au rôle du CD81 dans la chimiorésistance et sur les différentes voies de signalisation cellulaire en étudiant le profil d'expression génique.En conclusion, le CD81 semble être un nouveau marqueur pronostique des LAM ainsi qu'une cible potentielle de traitement de ces pathologies. / CD81 is a cell surface protein which belongs to the tetraspanin family. While in multiple myeloma its expression on plasma cells is associated with worse prognosis, this has not yet been explored in acute myeloid leukemia (AML). We measured membrane expression of CD81 on AML cells at diagnosis, evaluated its association with AML characteristics and its influence on patient outcome after intensive chemotherapy in a cohort of 134 patients. CD81 was detected in 92/134 (69%) patients. Patients with AML expressing CD81 had elevated leukocyte count (p=0.02) and were more likely classified as intermediate or adverse-risk by cytogenetics (p<0.001). CD81 expression had a negative impact on survival (event-free [EFS], overall [OS] and relapse-free survival [RFS]) in univariate (p<0.001) and in multivariate analyses (p=0.003, 0.002 and <0.001, respectively). CD81 has a negative impact on OS in patients with NPM1 mutation (p=0.01) and in favorable risk patients by European Leukemia Net (ELN) classification (p=0.002).Since aberrations in cell cycle signaling can cause drug resistance, tumor growth and aggressiveness we measured Ki67 on primary blast cells from AML patients. We considered 10 bone marrow samples from AML patients with either weak CD81 expression (less than 20% of blast cells) or 10 bone marrow samples with strong CD81 expression on blasts. We found a significant lower ki67 expression on blast cells from CD81 positive patients compared with those from CD81 negative patients (p<0.001), indicating a potential role of CD81 in cell cycle control. Furthermore, we investigated the role of CD81 in chemotherapy resistance and investigated potentially implicated signaling pathways by gene expression profiling.In conclusion, the cell surface marker CD81 may be a new prognostic marker for diagnostic risk classification and a new potential therapeutic target for drug development in AML.

Hematopoiesis is a highly orchestrated process, in which a single hematopoietic stem cell (HSC) gives a rise to all blood cellular components. For myeloid and lymphoid development precise controlled expression of the PU.1 transcription factor is needed. Deletion of PU.1 gene in mouse is lethal and its dysregulation during hematopoietic differentiation is associated with blood malignancies including acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). MDS and AML are serious blood disorders characterized by expansion of immature blood cells and lack of differentiated functional cells. Not only genetic but also epigenetic aberrations represent a very important field for studying pathophysiology of leukemia genesis and dysregulation of the PU.1 gene represents intensively studied candidate mechanism. Modern therapy of selected MDS and subset of AML patients is based on treatment with DNA hypomethylating agent Azacytidine (AZA) interfering in PU.1 gene regulatory mechanism. However, poor response or resistance to this therapy often occurs. In this thesis we present data obtained from AZA-resistant clones of MDS/AML cell line OCI-M2. We analysed DNA methylation and DNA hydroxymethylation at the key regulatory element of the PU.1 gene (URE). We found that these epigenetic modifications at URE...

61 Summary Wilms' tumor gene 1 (WT1) is highly expressed in acute leukemia and other hematological malignancies. It has been therefore suggested as a potential universal marker of minimal residual disease (MRD), particularly in patients with acute myeloid leukemia (AML). Due to controversial results of some of the studies, the role of WT1 in MRD follow-up and WT1 prognostic significance remain unclear. WT1 protein is produced in more than 36 different isoforms. These variants have distinct, partially overlapping functions and their ratio is supposed to influence the final effect of WT1. However, despite the increasing number of studies, the clinical impact of WT1 and its isoforms in acute leukemia have not yet been elucidated. We established a unique qPCR method to assess the expression pattern of the main 4 WT1 isoforms. Using this method, we determined the ratio of WT1 variants in the samples of patients with AML, myelodysplastic syndrome (MDS) and healthy controls. Our data showed that this pattern can distinguish among particular hematological malignancies, but lacks a prognostic significance. Within our international study group we determined the prognostic significance of total WT1 expression in childhood AML. Based on our results of a large cohort of patients we can conclude that WT1 expression at...

Viruses are known to be associated with 20% of human cancers. Epstein Barr virus (EBV) in particular is the first virus associated with human cancers. Here, we computationally detect EBV and explore the effects of this virus across cancers by taking advantage of the fact that EBV microRNAs (miRNAs) and Epstein Barr virus small RNAs (EBERs) are expressed at all viral latencies. We identify and characterize two sub-populations of EBV positive tumors: those with high levels of EBV miRNA and EBERS expression and those with medium levels of expression. Based on principal component analysis (PCA) and hierarchical clustering of viral miRNAs across all samples we observe a pattern of expression for these EBV miRNAs which is correlated with both the tumor cell type (B cell versus epithelial cell) and with the overall levels of expression of these miRNAs. We further investigated the effect of the levels of EBV miRNAs with the overall survival of patients across cancers. Through Kaplan Meier survival analysis we observe a significant correlation with levels of EBV miRNAs and lower survival in adult AML patients. We also designed a machine learning model for risk assessment of EBV in association with adult AML and other clinical factors. Our next aim was to identify targets of EBV miRNAs, hence, we used a combination of previously known methodologies for miRNA target detection in addition to a multivariable regression approach to identify targets of these viral miRNAs in stomach cancer. Finally, we investigate the variations across EBV subtype specific EBNA3C gene which interacts with the host immune system. Preliminary data suggests potential regional variations plus higher pathogenicity of subtype 1 in comparison to subtype 2 EBV. Overall, these studies further our understanding of how EBV manipulates the tumor microenvironment across cancer subtypes.

No description available.