ALBERT

Beschreibung: Background. The prognostic role of cell of origin profile (COO) assessed by immunohistochemistry (IHC) is controversial in Rituximab era. FIL conducted a phase III randomized trial aimed at investigating the benefit of intensification with high dose therapy plus autotransplant compared to R-dose-dense therapy as first line in young DLBCL at poor risk (aa-IPI 2-3). Clinical results were reported (Vitolo, ASH 2012). The aim of BIO-DLCL04 was to correlate the biological markers with PFS. Patients and Methods. From 2005 to 2010, 412 untreated DLBCL at aa-IPI 2-3 were enrolled. Central histology revision was mandatory and 13 patients were excluded due to different histologies. Biological markers were analyzed on DLBCL NAS; COO analysis was performed by IHC and cases were classified in germinal center (GC) and non-GC according to Hans' algorithm; COO determined by gene expression profile using the NanoString® nCounter® Analysis System based on 20-gene assay (Lymph2Cx) using formalin fixed paraffin embedded tissue is ongoing; BCL2, BCL6 and MYC anomalies were tested by IHC; final analysis by fluorescent in situ hybridization (FISH) is ongoing. Cases were deemed positive if at least 30% of lymphoma cells were stained with each antibody (with the exception of at least 40% for MYC). Results. At the time of this analysis, 223 DLBCL NAS were analyzed: 131 non-GC and 92 GC; BCL2, BCL6 and MYC anomalies were tested in 196, 74 and 107 cases respectively. Clinical characteristics for non-GC vs GC were: median age 51 years for both, male 49% vs 45%, aa-IPI 3 15% vs 25%, bone marrow involvement (BM) 16% vs 24%. R-HDC was performed in 45% of non-GC patients and in 49% of GC. Complete response was recorded in 105 (80%) non-GC patients and in 62 (67%) GC. At a median follow-up of 49 months, the 3-year PFS for non-GC vs GC was 75% (95% CI: 67-82) vs 57% (95% CI: 46-67) with crude hazard ratio, HR 0.55 (0.35-0.87), p.01 and adjusted (for age, gender, aa-IPI, BM) aHR 0.56 (0.35-0.88), p.013. No significant differences by treatment were reported. Overexpression of MYC by IHC had a relevant prognostic impact, with aHR 1.84 (0.99-3.44), p.054. By IHC, 3-years PFS for double negative vs single BCL2 or MYC overexpression vs double positive, was 85% vs 68% vs 51% respectively, with an aHR for double expressors compared to double negative of 3.91 (1.13-13.53), p.031. At the time of the present report, FISH analysis was conducted in 88 cases: 43 were triple negative, 37 single hit and 8 double/triple hit. By FISH, 3-years PFS for triple negative vs single hit vs double/triple hit was 74% vs 84% vs 25% respectively, with an aHR for double/triple hit compared to triple negative of 5.73 (2.05 to 16.02), p.001. Conclusions. In conclusion, with the limit of the analysis performed by IHC based on Hans' algorithm, BIO-DLCL04 showed an unexpected better outcome for non-GC compared to GC, irrespective of treatment arm. The ongoing analysis conducted by Nanostring will be more informative. The overexpression of MYC was an unfavourable risk factor, mainly if associated with BCL2 overexpression, irrespective of type of treatment. Moreover, double/triple hit patients represent a subgroup with extremely poor prognosis. High dose therapy plus autotransplant was not able to reverse the inferior outcome of neither double expressors nor double hit patients and new strategies are deemed for these poor prognosis patients. Disclosures No relevant conflicts of interest to declare.

Beschreibung: Abstract 773 Peripheral T-cell lymphomas (PTCLs) are rare and heterogeneous tumors whose biology is largely unknown. Interestingly, the commonest subtypes (i.e. PTCL not otherwise specified, NOS; angioimmunoblastic T-cell lymphoma, AITL; and anaplastic large cell lymphoma, ALCL) present on one hand few disease-specific molecular features and, on the other hand, several apparently common abnormalities. So far, no data are available regarding miRNA expression in these tumors. In order to identify miRNA deregulated in PTCLs, we performed an extensive miRNA profiling (by studying 379 targets on the TaqMan Array MicroRNA Cards) of 44 PTCLs (including 23 PTCLs/NOS, 12 ALCLs, and 9 AITLs) and 13 sample representative of normal T-cell sub-populations (CD4+ and CD8+, both resting and activated). In addition, for all these cases, gene expression profiles (GEPs) were generated by the Ilumina whole genome DASL-assay. TaqMan Quantitative-PCR (qPCR) was then used for validation. First, we found that PTCLs and normal T-cells could be easily distinguished based on their miRNA profile, by both unsupervised and supervised analysis. Specifically, the latter identified 91 miRNA differentially expressed in PTCLs vs. T-cells with a fold change ≥2 and a pvalue

Beschreibung: Background. Follicular lymphoma (FL) is usually classified as grade (G) I, II or III. Grade III is further subdivided into GIIIa and GIIIb, the latter almost exclusively consisting of CBs. However, this distinction is questioned. Recently, gene expression studies showed that clinical aggressiveness can be associated with specific molecular signatures partially independent from histological grade and that immune reactive cells can play a major role in the outcome determinism. However, to date, gene expression studies did not provide molecular rationale for histological grading and it is still debated if including FL GIIIb within FL or DLBCL. We studied the gene expression profile (GEP) of 43 FLs, 50 B-cell non-Hodgkin lymphomas (B-NHLs) of different histotypes, and 20 samples of normal B-lymphocytes in order to assess: the relationship of FL with normal B-cells and other B-NHLs; whether FL is a unique disease; and whether FL GIIIb is closer to FL or diffuse large B-cell lymphoma of the germinal center B-cell type (GCB-DLBCL). Methods. Forty-three FL cases were analyzed. Of these, 37 corresponded to cryopreserved tissue blocks and 6 to enriched neoplastic cells All the samples were obtained at the time of diagnosis, before treatment administration. In addition, samples of normal B-cell sub-populations including CB (N=5), centrocytes (CC, N=5), naïve, N (N=5), and memory cells, M (N=5) were studied. Finally, a panel of B-NHLs was analyzed including Burkitt’s lymphoma (BL, N=4), DLBCL, (N=16), mantle cell lymphoma (MCL, N=10), hairy cell leukemia (HCL, N=10), and B-cell chronic lymphocytic leukemia (B-CLL, N=10). Finally, in silico data concerning 37 cases of germinal center B-cell type (GCB) DLBCL were retrieved at http://www.ncbi.nlm.nih.gov/projects/geo/. For proper comparison with our samples, gene expression values were normalized “per gene” and “per chip”. For microarray analysis, fragmented cRNA was hybridized to HG-U133 2.0 plus microarray. Results. First, we found that the molecular profile of FL is intimately related to that of normal germinal centre B-cells, irrespectively of the histological grade. However, interestingly, several cell programs are regulated as in memory cells. Secondly, we observed that FL has a relatively homogeneous GEP that is distinct from that of other B-NHLs and does not include discrete molecular subgroups. However, by further clustering samples according to signatures differentially expressed among FLs or in FL vs. DLBCL, we showed that GI-IIIa tumors tend to cluster together, while GIIIb FL constitutes a distinct subgroup. Finally, we found that the molecular signature of GIIIb FL is indeed closer to that of the other FLs than to the one of GCB-DLBCL. These data support the hypothesis that GIIIb FL belongs to FL rather than DLBCL, and sustain the possible revision of FL histological grading, with the simple distinction into FL (GI-IIIa) and FL/large cell (GIIIb).

Beschreibung: Abstract 3879 Purpose. The use of early (interim) positron emission tomography (PET) restaging during front-line therapy in Hodgkin's lymphoma (HL) has considerably increased in clinical practice as an early recognition of treatment failure allows patients to be addressed to more intensive treatment regimens. Patients and Methods. Between June 1997 and June 2009, 304 newly-diagnosed Hodgkin's lymphoma patients (147 early-stage and 157 advanced-stage) were treated with the ABVD regimen at two Italian institutions. Patients underwent to a PET staging and restaging at baseline, after 2 cycles of therapy and at the end of the treatment. Results. 53 patients showed a positive interim PET and only 13/53 (24.5%) achieved a complete response (CR), whereas 251 patients showed a negative PET and 231/251 (92%) remained in CR. Comparison between interim PET-positive and interim PET-negative patients indicated a significant association between PET findings and 9-year progression-free survival (p=0.0000) and 9-year overall survival (p=0.0000), with a median follow-up of 31 months. Among the early-stage patients, 19 had a positive interim PET and only 4 (21%) achieved a CR; among the 128 negative interim PET patients, 122 (97.6%) obtained a CR. In the advanced-stage subset, 34 patients showed a persistently positive PET (with only 9/34, 26.4% in CR), whereas 123 showed a negative interim PET, with 109 (88.6%) remaining in CR. Conclusions. Our results confirm the role of early PET as a significant step forward for the management of both early and advanced-stage HL patients, offering the potential for an immediate switch to high-dose treatments, if required. Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Abstract 2494 Background. Burkitt lymphoma (BL) is currently listed in the WHO classification of lymphoid tumors as a single genetic and morphological entity with variation in clinical presentation. In particular, three clinical subsets of BL are recognized: endemic (eBL), sporadic (sBL) and immunodeficiency associated (ID-BL). Each affects different populations and can present with different features. So far, possible differences in their gene expression profiles (GEP) have not been investigated. In this study we aimed to 1) assess whether BL subtypes present with differences in their GEP; 2) investigate the relationship of the different BL subtypes with the non-neoplastic cellular counterparts; 3) Identify genes and programs specifically deregulated in BLs and possibly contributing to the malignant phenotype. Methods. We studied by GEP 128 cases of B-cell derived malignancies and 20 samples of normal B-cell subpopulations GEP analysis. In particular, we included 40 BLs (13 eBLs, 21 sBLs 6 HIV-BLs), 40 follicular lymphomas, 10 chronic lymphocytic leukemias, 10 GCB-type diffuse large B-cell lymphomas, 10 ABC-type DLBCL, 5 primary mediastinal B-cell lymphomas, 13 HIV-related DLBCL, as well as 10 germinal center (GC), 5 naïve and 5 memory cells samples. GEP results were confirmed by dividing BL cases into training and test subgroups. In addition, as further validation, we performed immunohistochemistry (IHC) on tissue microarrays containing 85 BL cases as well as functional assays in vitro and in vivo, by focusing on the role of RBL2, a tumor suppressor gene involved in cell cycle control and mutated in eBL. Specifically, we used cell transfection and shRNAs (for mimicking MYC over-expression and RBL2 silencing), soft agar and invasion capability assays, and xenografted mouse models. Results. First, we found that BLs constitute a unique molecular entity, with a relatively homogeneous GEP, distinct from other B-cell malignancies. Indeed, by unsupervised analysis all BLs clearly clustered apart of other lymphomas. However, by supervised analysis, we found that BL subtypes presented slight differences in their GEPs. Particularly, eBLs and ID-BLs appeared to be almost identical, diverging from sBLs. Specifically, they varied for genes involved in cell cycle control, BCR-signaling, and TNF/NFKB-pathways. Of note, eBLs and ID-BLs on one hand, and sBLs on the other (roughly corresponding to EBV+ vs. EBV− cases) also differed for genes target of mi-R127a, which is altered in EBV+ cases as a direct consequence of viral integration. To further investigate cell cycle regulation in BLs, we inferred a network of RBL2-depending genes by reverse engineering, by uncovering possible RBL2 transcriptional targets. Interestingly, we found that eBL and sBL diverged for genes belonging to such network. Notably, we provided evidences that RBL2 can cooperate with MYC in inducing a neoplastic phenotype in vitro and in vivo. In particular, lymphoblastoid cells engineered to carry both MYC over-expression and RBL2 silencing presented with increased colony formation and matrix invasion capabilities, and higher efficiency in inducing tumor formation in nude mice if compared to single transfectants (MYC+ or RBL2−). Moreover, as the present WHO classification does not definitely identify the counterpart of eBL, we compared BLs GEP to those of normal B-cells. We found that all BL subtypes were intimately related to GC cells (by showing an early stage GC differentiation arrest), differing from them for molecules specially involved in cell proliferation, immune response, and signal transduction. Finally, as further validation of GEP, we studied by IHC the expression of SPARC and CYR61, two molecules involved in human tumorigenesis. Indeed, they turned out to be consistently expressed by neoplastic elements in all instances, as indicated by GEP analysis. Conclusions. Our study provided substantial insights on the pathobiology of BLs, by offering novel evidences which may be relevant for its classification and possibly future treatment. Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Splenic marginal zone lymphoma (SMZL) is one of the few B-cell lymphoma types that remain orphan of molecular lesions in cancer-related genes. Detection of active NF-κB signaling in 14 (58%) of 24 SMZLs prompted the investigation of NF-κB molecular alterations in 101 SMZLs. Mutations and copy number abnormalities of NF-κB genes occurred in 36 (36%) of 101 SMZLs and targeted both canonical (TNFAIP3 and IKBKB) and noncanonical (BIRC3, TRAF3, MAP3K14) NF-κB pathways. Most alterations were mutually exclusive, documenting the existence of multiple independent mechanisms affecting NF-κB in SMZL. BIRC3 inactivation in SMZL recurred because of somatic mutations that disrupted the same RING domain that in extranodal marginal zone lymphoma is removed by the t(11;18) translocation, which points to BIRC3 disruption as a common mechanism across marginal zone B-cell lymphomagenesis. Genetic lesions of NF-κB provide a molecular basis for the pathogenesis of more than 30% of SMZLs and offer a suitable target for NF-κB therapeutic approaches in this lymphoma.

Beschreibung: Abstract 4631 Background Peripheral T cell lymphomas (PTCLs) are a heterogeneous group of tumors representing approximately 12% of lymphoid neoplasms, basically subdivided into specified and not specified (NOS) forms. PTCL/NOS, corresponding to about 60%–70% of PTCLs, cannot be further classified on the basis of morphology, phenotype, or conventional molecular studies. Clinically, PTCLs/NOS are highly aggressive lymphomas, with a poor response to therapy, and dismal overall survival (20-30%). Their pathobiology is poorly known, though recent gene expression profiling (GEP) studies have provided some hints for better understanding their pathogenesis. In particular, GEP and immunohistochemical studies on tissue-microarrays (TMAs) demonstrated PDGFRA to be systematically activated in almost all PTCLs/NOS, by nominating it as potential therapeutic target. Aims In this study, we aimed to identify the determinants of PDGFRA activation in PTCL/NOS. Specifically, we studied PDGFRA locus in order to identify possible mutations, translocations, or copy number variations and we explored the possible existence of an autocrine/paracrine loop sustaining an otherwise integer kinase. Methods The PDGFRA locus (4q1.1-4q1.3) was studied by FISH and wide-genome SNPs analysis (Affymetrix 500K Array). Direct sequencing of all PDGFRA exons and introns as well as of the promoter region was also performed in 90 cases. IHC and ELISA were adopted in order to study the expression of PDGF-A, PDGF-B and PDGF-C on tissue sections and in supernatants from PTCL/NOS cell cultures, respectively. Finally, the expression of PDGFRA and its activated (phosphorilated) form, p-PDGFRA, was assessed by IHC on TMAs, and by flow-citometry in PTCL/NOS cultured cells as well as in a FIP1L1-PDGFRApos chronic eosinophilic leukemia cell line (EOL-1) before and after the exposure to an anti-PDGF ligand neutralizing antibody (R&D System), given at various concentrations (20-40-60-80 ug/mL). Vitality assessments, proliferation/cell cycle assay (by In Situ Cell Proliferation kit, FLUOS – Roche) and evaluation of PDGFRA and p-PDGFRA were performed at 24, 48, 96 hours. A human PDGF peptide (R&D Sytems) was added to cultured cells for 6 hours to evaluate whether PDGFRA de-phosphorilation was really due to PDGF ligand remotion. Results First, FISH, SNPs analysis and direct sequencing showed preserved integrity of PDGRA locus. Thus we tested the hypothesis of an autocrine/paracrine stimulation. PDGF-A, PDGF-B and PDGF-C were found to be expressed by neoplastic cells at IHC in 93-95% of cases. In addition, PDGF-AA was found to be secreted by cultured neoplastic cells by ELISA. Notheworthy, PTCL cells secreted much more ligand than any other cell taken as control. We then tested whether PDGFRA phosphorylation was actually due to the presence of a PDGF ligand. Indeed, PTCL cells treated with anti-PDGF ligand neutralizing antibody at various concentrations showed PDGFRA dephosphorilation ranging from 30% up to 90% in a time dependent manner. Notably, the effect was specific as in EOL-1 PDGFRA phosphorylation was not modified at all. In addition, PTCL cells treated with a minimum of 20ug/mL of anti-PDGF ligand neutralizing antibody for 48h showed a 70% blockade of proliferation in comparison to untreated cells (BrdU assay). A further addition of 20 ug/ml of inhibitory antibody at 48 hours, increased the proliferation arrest up to 80% at 96 hours. Finally, the addition of a natural human PDGF peptide to cells previously treated with the anti-PDGF antibody, could restore PDGFRA phosphorylation confirming that PDGFRA de-phosphorilation was due to ligand remotion. Conclusions Taken together, our data demonstrate that PDGFRA activity is sustained by an autocrine loop in PTCL/NOS. In fact, though, in vivo, a possible additive paracrine effects mediated by reactive components cannot be excluded, we provide evidence that the phenomenon is largely due to neoplastic cells. Importantly, as PDGFRA signaling abrogation was associated to proliferation arrest, PDGFRA was confirmed as potential therapeutic target. Acknowledgments: this work was supported by Centro Interdipartimentale per la Ricerca sul Cancro “G. Prodi”, BolognAIL, AIRC, FIRB, RFO, Fondazione Cassa di Risparmio in Bologna, Fondazione della Banca del Monte e Ravenna, Progetto Strategico di Ateneo 2006, and Vanini-Cavagnino grant. Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Abstract 595FN2 Introduction: Mantle cell lymphoma (MCL) is an incurable B-cell non-Hodgkin lymphoma characterized by aberrant genetic (t(11;14)(q13;q32)) and epigenetic (DNA hypermethylation) dysregulation. Chromatin remodeling complexes and associated co-repressors such as histone deacetylases (HDAC), DNA methyltransferases (DNMT) and protein arginine methyltransferase 5 (PRMT5), are involved in silencing tumor suppressor and regulatory gene expression and may contribute to B-cell transformation. PRMT5 silences the transcription of key regulatory genes by symmetric di-methylation (S2Me) of arginine (R) residues on histone proteins (H4R3 and H3R8). We have previously identified PRMT5 over expression to be relevant to MCL pathogenesis and shown it to work concertedly with HDAC2, methyl-CpG binding domain protein 2 (MBD2) and DNMT3a to silence genes with anti-cancer and immune modulatory activities. siRNA-mediated knockdown of PRMT5 in MCL cell lines leads to growth arrest and apoptosis, thus, we explored methods to inhibit PRMT5 activity as a novel experimental therapeutic strategy for this disease. Methods and Results: A rational design of small molecule compounds to inhibit PRMT5 activity led us to construct an in silico model of the human PRMT5 catalytic domain based on available homologous crystal structures from Protein Data Bank (MODELLER9v1 software). We screened a library of 10,000 compounds and eight small molecules were identified for biological investigation based on binding energy in the PRMT5 catalytic site. Enzyme inhibition assays using purified PRMT1 (type I PRMT) and PRMT5 (type II PRMT) showed that two compounds (BLL1 and BLL3) were capable of selectively inhibiting PRMT5 and not PRMT1 activity (p