ALBERT

Description: PTCL are a heterogeneous group of uncommon lymphoid malignancies. Geographical differences have been reported, the NK/T-cell-derived nasal type being more common in Asia and the entheropathy-type more common in western countries. Except for the alk-positive anaplastic large cell lymphoma (ALCL) subtype, PTCL have generally a poorer outcome than their B-cell counterparts when treated with conventional therapeutic strategies. In recent years, as a result of an improved biologic understanding and definition of PTCL entities, an increasing number of PTCL-specific clinical trials have been initiated. The purpose of this analysis was to describe epidemiological and clinico-pathological features of the major subtypes in PTCL, as they occur in an unselected western population, in order to provide population-based data that may be useful for the design of future PTCL-specific studies. Although the LYFO registry was initiated in 1983, the present analysis only includes patients diagnosed in the 15-year period from 1990 (when immunhistochemistry was routinely applied to all biopsy specimen) to 2004. Within this 15 yr period, 485 PTCL cases were diagnosed. They had an age range of 16–92 yrs and a male to female ratio of 1.4 (59% male and 41% female cases). The most frequent histological subtypes were PTCL unspecified (PTCLu) (44%), non-cutaneous ALCL (alk-status not available) (35%) and angioimmunoblastic (AIL) (17%). The incidence trend for PTCL, taken as one group, did not show significant changes over the 15 years observation period. Approximately two thirds of the patients (65%) had disseminated disease (stage III–IV) at diagnosis, while half of the patients (49%) presented with B-symptoms. AIL had a higher frequency of cases with disseminated disease (93%, p

Description: Introduction: Tumor boards have become a crucial institution in oncology practice to provide paramount interdisciplinary cancer treatment, stream-line patient (pt) entries and to ensure treatment according to clinical pathways (CP). We initiated a weekly MM-TB at our institution in 6/2012. Participating experts are hematologist-oncologists, pathologists/cytogenetic specialists, orthopedists, radiotherapists, immunologists/rheumatologists and, if needed, nephrologists, cardiologists and others. Pt applications to be discussed are centrally organized through our CCCF, with the TB advice being centrally stored within our electronic pt information system. Recommended TB advice is made according to best current literature/knowledge and international CP. The development of mandatory CCCF-CP and transparency of decision making are key quality criteria. Methods: This first analysis focused on a) discussed TB questions, b) given recommendations, c) pt characteristics, d) pts’, referring- and participating-physicians' satisfaction with the TB, e) inclusion of these challenging-to-treat pts in clinical trials (CT) and f) PFS/OS of TB pts as compared to the literature (Kumar SK. Leukemia 2012). Grades of recommendations were assigned using the GRADE criteria (Engelhardt M. Haematologica 2014) and meticulously assessed, as well as whether TB recommendations were pursued. Pts’, referring- and participating-physicians' satisfaction with the TB was evaluated via standardized questionnaires, the aimed sample size being n=100 for consecutive pts and ~n=30 each for participating and referring physicians. Results: From 6/2012-5/2014, 483 pts have been discussed within 90 MM-TB sessions, substantially increasing these from 2011 to 2012, 2013 and 2014 by 12-fold. Of the entire MM cohort seen at our institution, 60% of these challenging-to-treat pts were discussed within the TB in 2012, increasing to 71% in 2013. We have currently assessed 200 TB-protocols for pt characteristics, clinical outcome and adherence to TB decisions. Of those, 2% were presented for explicit diagnosis-finding, 17% had newly diagnosed MM, 41% relapsed/refractory MM and 40% had attained stable disease or better with their last-line therapy and were discussed to resolve their ongoing treatment. Expectedly, most pts (89%) were discussed for their next-line treatment, 43% due to strains with comorbidities, symptom control, side effects, diagnosis finding and MM-staging, and 11% due to various other reasons (multiple entries possible). Mean treatment lines of pts discussed in the TB was 2 (range 0-10), deciding on their 3rd-line-treatment. Within the TB cohort, 70% were presented once, but 30% several times (mean 2, range 2-4). Of these multiple presentations, most pts had relapsed or refractory MM, this rate further increasing towards the 3rd and 4th TB-presentation. The adherence to TB-recommendations was excellent with 93% of decisions being pursued. Reasons for adapted approaches were practicable issues or disagreement of the pt, family or referring physician. Of currently 80/100 interviewed pts, 95% were entirely satisfied with their care, treating oncologists/MM-expert team and very supportively perceived the MM-TB. Of note, 94% considered their cancer care ideally achieved by the TB, 92% that their local physician profited greatly and 88% that their personal preferences were also accounted for. Of 30 interviewed participating physicians, 97% considered themselves well-educated and their time well-spent. Of currently 18 referring physicians, 73% were unconditionally satisfied with all TB-diagnostics and -therapies, with the university centers' cooperation and 65% acknowledged no information loss. Of 288 pts assessed for their CT suitability, 28% were suggested by the TB to be included, with 53% actually being able to enter therein. Thus, 15% of our MM-TB cohort could be included in a CT, which is considerable since these were challenging-to-treat pts who had received extensive prior therapies and showed several comorbidities. This also confirms current CT accrual rates for cancer pts of 5-15%, which can be increased with well-structured TB. Conclusions: Our preliminary results suggest that this MM-TB is a highly relevant exchange platform and allows physicians from different disciplines to intensely and rewardingly collaborate for state-of-the-art cancer care. Disclosures No relevant conflicts of interest to declare.

Description: The FOXO transcription factors control proliferation and apoptosis in different cell types. Their activity is regulated by posttranslational modifications, mainly by the PI3K-PKB pathway, which controls nuclear export and degradation. We show that FOXO1 is highly expressed in normal germinal center B cells as well as in non-Hodgkin lymphomas, including follicular lymphoma, diffuse large B-cell lymphoma, mucosa-associated lymphoid tissue non-Hodgkin lymphoma, B-cell chronic lymphocytic leukemia, and mantle cell lymphoma. In contrast, in 31 of 32 classical Hodgkin lymphoma (cHL) cases, Hodgkin and Reed-Sternberg cells were FOXO1 negative. Neoplastic cells of nodular lymphocyte-predominant Hodgkin lymphoma were negative in 14 of 20 cases. FOXO1 was down-regulated in cHL cell lines, whereas it was expressed in non-Hodgkin lymphoma cell lines at levels comparable with normal B cells. Ectopic expression of a constitutively active FOXO1 induced apoptosis in cHL cell lines and blocked proliferation, accompanied with cell-cycle arrest in the G0/G1 phase. We found that, in cHL cell lines, FOXO1 is inactivated by multiple mechanisms, including constitutive activation of AKT/PKB and MAPK/ERK kinases and up-regulation of microRNAs miR-96, miR-182, and miR-183. These results suggest that FOXO1 repression contributes to cHL lymphomagenesis.

Description: The survival of diffuse large B-cell lymphoma patients varies considerably, reflecting the molecular diversity of tumors. In view of the controversy whether cytologic features, immunohistochemical markers or gene expression signatures may capture this molecular diversity, we investigated which features provide prognostic information in a prospective trial in the R-CHOP treatment era. Within the cohort of DLBCLs patients treated in the RICOVER-60 trial of the German High-Grade Lymphoma Study Group (DSHNHL), we tested the prognostic impact of IB morphology in 949 patients. The expression of immunohistochemical markers CD5, CD10, BCL2, BCL6, human leukocyte antigen (HLA)–DR, interferon regulatory factor-4/multiple myeloma-1 (IRF4/MUM1), and Ki-67 was assessed in 506 patients. Expression of the immunohistochemical markers tested was of modest, if any, prognostic relevance. Moreover, the Hans algorithm using the expression patterns of CD10, BCL6, and interferon regulatory factor-4/multiple myeloma-1 failed to show prognostic significance in the entire cohort as well as in patient subgroups. IB morphology, however, emerged as a robust, significantly adverse prognostic factor in multivariate analysis, and its diagnosis showed a good reproducibility among expert hematopathologists. We conclude, therefore, that IB morphology in DLBCL is likely to capture some of the adverse molecular alterations that are currently not detectable in a routine diagnostic setting, and that its recognition has significant prognostic power.

Description: Introduction The combination of bortezomib, doxorubicin and dexamethasone (BDD) is well tolerated and induces a high overall response rate (ORR). Preclinical studies have demonstrated that vorinostat, a histone deacetylase inhibitor, is synergistic with bortezomib and doxorubicin. The aim of this phase I/II study was to determine the tolerability and activity of the combination of BDD with vorinostat (VBDD) in relapsed/refractory multiple myeloma (MM). Methods Patients received escalated vorinostat-doses (provided by MSD) at 100mg (dose level 0), 200mg (dose level +1) and 300mg (dose level+2) on days 1-4, 8-11, 15-18, combined with bortezomib 1.3mg/m2 day 1,8,15 (provided by Janssen), dexamethasone 40mg day 1,8,15,22 and doxorubicin on 9mg/m2 day 1+8. The primary objective was the maximum tolerated dose (MTD; 3+3 dose escalation design). Secondary objectives were safety, response assessed by EBMT and IMWG criteria, progression-free survival and overall survival. Correlative endpoints include prognostic MM-parameters, organ function, QoL-, comorbidity-assessments and translational studies (e.g. HDAC-activity in PB MNCs, Figure 1). Dose limiting toxicities (DLTs) were defined as any possibly drug related adverse events (AEs) ≥grade 3 (CTCAE) within the 1st cycle. After completion of 6 cycles, patients could continue with bortezomib maintenance therapy or proceed to (most often 2nd) ASCT. Results To date, 18/30 patients have been enrolled (median age 63 years [range 54-75], 55% men). The median Karnofsky Performance Status was 90% (range 70-100%). Median prior therapy lines were substantial with 3 (range 1-8): bortezomib, thalidomide or lenalidomide were given in 88% and 24% each, respectively; 94% of patients had undergone prior SCTs. Cytogenetic abnormalities included del(17p) (n=2), t(4;14) (n=2), gain(1q) (n=2), t(11;14) (n=4) and hyperdiploidy (n=7). No DLTs have been observed to date; with 3 patients each being included in dose level 0 and dose level +1 and the following patients safely proceeding to dose level +2. Six SAEs occurred in 4/18 patients (22%): bacteraemia (n=1) and herpes zoster reactivation (n=1) were suspected to be related to all VBDD-drugs. No causal relationship to study drugs was suspected for pneumonia (n=2), 1 syncope and 1 death due to PD with persisting plasma cell leukemia. The ORR (〉PR) and clinical benefit rate (SD, PR, CR) was 65% and 89%, respectively. At a median follow-up of 8 months (range 3-23), there have been only 2 patients with PD (refractory MM + plasma cell leukemia). The analysis of HDAC activity after VBDD initiation demonstrated downregulation in 6/8 (75%) patients (Figure 1). Further analyses will determine, whether HDAC activity and treatment response may correlate and whether this HDAC downregulation may precede and/or indicate depth of response Conclusions VBDD is a well tolerated and effective regimen in heavily pretreated relapsed/refractory MM patients. There have been no observed DLT and the MTD of vorinostat was set at 300mg, with all reported SAEs being in line with the known safety profile of the investigated drugs. Our alternative vorinostat-schedule (dosing of 4 days on and 4 days off) induced excellent tolerability and seems to enhance the antimyeloma response, warranting completion of this study. Disclosures: Kleber: MSD, Janssen-Cilag: Research Funding. Off Label Use: Preclinical studies have demonstrated that vorinostat, a histone deacetylase inhibitor, is synergistic with bortezomib and doxorubicin. The aim of this phase I/II study was to determine the tolerability and activity of the combination of BDD with vorinostat (VBDD) in relapsed/refractory multiple myeloma. Vorinostat is off-label use for MM patients, all other drugs are in label use. Waesch:MSD, Janssen-Cilag: Research Funding. Engelhardt:MSD, Janssen-Cilag: Research Funding.

Description: IL-33 is a recently discovered cytokine involved in induction of Th2 responses and functions as an alarmin. Despite numerous recent studies targeting IL-33, its role in vivo is incompletely understood. Here we investigated inflammatory responses to intraperitoneal IL-33 injections in wild-type and mast cell–deficient mice. We found that wild-type mice, but not mast cell–deficient Wsh/Wsh mice, respond to IL-33 treatment with neutrophil infiltration to the peritoneum, whereas other investigated cell types remained unchanged. In Wsh/Wsh mice, the IL-33–induced innate neutrophil response could be rescued by local reconstitution with wild-type but not with T1/ST2−/− mast cells, demonstrating a mast cell–dependent mechanism. Furthermore, we found this mechanism to be partially dependent on mast cell–derived TNF, as we observed reduced neutrophil infiltration in Wsh/Wsh mice reconstituted with TNF−/− bone marrow–derived mast cells compared with those reconstituted with wild-type bone marrow–derived mast cells. In agreement with our in vivo findings, we demonstrate that humanneutrophils migrate toward the supernatant of IL-33–treated human mast cells. Taken together, our findings reveal that IL-33 activates mast cells in vivo to recruit neutrophils, a mechanism dependent on IL-33R expression on peritoneal mast cells. Mast cells activated in vivo by IL-33 probably play an important role in inflammatory reactions.

Description: Primary mediastinal B-cell lymphoma (PMBL) is a separate entity of aggressive B-cell lymphoma, characterized by a constitutive activation of janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway, also observed in Hodgkin lymphoma. Although many cancers exhibit constitutive JAK-STAT pathway activation, mutations of STAT genes have not been reported in neoplasms. Here, we show that MedB-1 PMBL-derived and L1236 Hodgkin-derived cell lines and 20 of 55 (36%) PMBL cases harbor heterozygous missense mutations in STAT6 DNA binding domain, whereas no mutation was found in 25 diffuse large B-cell lymphoma samples. In 3 cases, somatic origin was indicated by the absence of the mutations in the nontumoral tissue. The pattern of STAT6 mutations was different from the classical features of somatic hypermutations. The mutant STAT6 proteins showed a decreased DNA binding ability in transfected HEK cells, but no decrease in expression of STAT6 canonical target genes was observed in PMBL cases with a mutated STAT6 gene. Although the oncogenic properties of STAT6 mutant proteins remain to be determined, their recurrent selection in PMBL strongly argues for their involvement in the pathogenesis of this aggressive B-cell lymphoma.

Description: The transcription factor KLF4 may act both as an oncogene and a tumor suppressor in a tissue-depending manner. In T- and pre-B-cell lymphoma, KLF4 was found to act as tumor suppressor. We found the KLF4 promoter methylated in B-cell lymphoma cell lines and in primary cases of B-cell lymphomas, namely, follicular lymphoma, diffuse large B-cell lymphoma, Burkitt lymphoma, and in classic Hodgkin lymphoma (cHL) cases. Promoter hypermethylation was associated with silencing of KLF4 expression. Conditional overexpression of KLF4 in Burkitt lymphoma cell lines moderately retarded proliferation, via cell-cycle arrest in G0/G1. In the cHL cell lines, KLF4 induced massive cell death that could partially be inhibited with Z-VAD.fmk. A quantitative reverse-transcribed polymerase chain reaction array revealed KLF4 target genes, including the proapoptotic gene BAK1. Using an shRNA-mediated knock-down approach, we found that BAK1 is largely responsible for KLF4-induced apoptosis. In addition, we found that KLF4 negatively regulates CXCL10, CD86, and MSC/ABF-1 genes. These genes are specifically up-regulated in HRS cells of cHL and known to be involved in establishing the cHL phenotype. We conclude that epigenetic silencing of KLF4 in B-cell lymphomas and particularly in cHL may favor lymphoma survival by loosening cell-cycle control and protecting from apoptosis.

Description: The spectrum of entities, the therapeutic strategy, and the outcome of mature aggressive B-cell non-Hodgkin lymphomas (maB-NHLs) differs between children and adolescents on the one hand and adult patients on the other. Whereas adult maB-NHLs have been studied in detail, data on molecular profiling of pediatric maB-NHLs are hitherto lacking. We analyzed 65 cases of maB-NHL from patients up to 18 years of age by gene expression profiling, matrix comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH), and immunohistochemistry. The majority of the analyzed pediatric patients were treated within prospective trials (n = 49). We compared this group to a series of 182 previously published cases of adult maB-NHL. Gene expression profiling reclassified 31% of morphologically defined diffuse large B-cell lymphomas as molecular Burkitt lymphoma (mBL). The subgroups obtained by molecular reclassification did not show any difference in outcome in children treated with the NHL-Berlin-Frankfurt-Muenster (BFM) protocols. No differences were detectable between pediatric and adult mBL with regard to gene expression or chromosomal imbalances. This is the first report on molecular profiling of pediatric B-NHL showing mBL to be much more prominent in children than suggested by morphologic assessment. Based on molecular profiling mBL is a molecularly homogeneous disease across children and adults.

Description: Abstract 2417 Primary mediastinal B-cell lymphoma (PMBL) is a subtype of diffuse large B-cell lymphoma (DLBCL) that affects predominantly young women (Swerdlow et al. 2008). Despite improvements due to addition of rituximab, which has become state of the art treatment, 20% of PMBL patients succumb to disease progression or relapse. Notably, here are currently no registered trials that are actively recruiting PMBL-patients and a better understanding of the underlying pathobiology may identify novel therapeutic targets and provide an alternative to dose escalation (Steidl and Gascoyne 2011). BCL6 is a key germinal center B-cell transcription factor that suppresses genes involved in lymphocyte activation, differentiation, cell cycle arrest and DNA damage response gene. BCL6 is aberrantly expressed in certain DLBCL subgroups and BCL6 overexpression is sufficient for lymphomagenesis in mice (Cattoretti et al. 2005). In cellular- and murine DLBCL models, targeting of BCL6 via retroinverted BCL6 peptid inhibitor (RI-BPI) appears effective (Polo et al. 2004; Cerchietti et al. 2010). In conjunction with the relatively restricted expression pattern of BCL6, these data collectively suggest BCL6 as a candidate for targeted therapy in BCL6-positive lymphomas. Despite substantial work on BCL6 in lymphomas, the function of BCL6 in PMBL is unknown. To address the BCL6 function in PMBL, we performed BCL6 depletion by siRNA in all three available PMBL cell lines: K1106, U-2940 and MedB-1. We found that BCL6 acts pro-proliferative and anti-apoptotic; however, PMBL models were only partially dependent on and not addicted to BCL6. Given that BCL6 expression in all PMBL cell lines is variable with a notable fraction of BCL6-negative cells, we argued that increasing the fraction of BCL6-positive cells might increase the level of BCL6-dependence. Since IL-4/STAT6 signaling upregulates BCL6 in mouse lymphocytes (Schroder et al. 2002), we treated PMBL cell lines with IL-4 (or IL-13) and, as expected, observed increased phosphorylated (p)STAT6 levels. Surprisingly, the pSTAT6 increase was not associated with higher – but with drastically lower BCL6 protein levels. Moreover, in untreated cells, co-localization studies for pSTAT6- and BCL6 demonstrated staining in mutually exclusive subsets of cells (Figure 1A), suggesting negative interaction between BCL6 and pSTAT6. Other STAT family members were already shown to participate in the transcriptional regulation of BCL6. Thus, we examined binding of STAT6 to the proximal promoter of BCL6 in all PMBL cell lines using shift assay and chromatin immunoprecipitation. We found that STAT6 can bind all five GAS binding sites within the BCL6 promoter in vitro and in all PMBL cell lines STAT6 was bound to proximal BCL6 promoter in vivo. Furthermore, transient STAT6 depletion by siRNA and/or ectopic expression of constitutively active STAT6 confirms that pSTAT6 is sufficient for transcriptional repression of BCL6. Co-localization studies in primary patient samples demonstrated mutually exclusive BCL6/pSTAT6 distribution as a visual hallmark of the repression mechanism (Figure 1B, C). Thus, our data demonstrate for the first time that constitutively active STAT6 transcriptionally represses BCL6 in PMBL. In conjunction with functional data, the delineated repression mechanism may prevent addiction to one single oncogenic pathway (i.e. BCL6) in PMBL. Figure 1. Mutually exclusive distribution of BCL6 and pSTAT6 in PMBL Figure 1. Mutually exclusive distribution of BCL6 and pSTAT6 in PMBL Disclosures: No relevant conflicts of interest to declare.