Hodgkin Reed-Sternberg Cells Research Articles

BCL2 Expression Correlates with Refractory and Relapsed Classic Hodgkin Lymphoma. Its Blokeadge As a Promising Directed-Therapy

Classic Hodgkin Lymphoma (cHL) is a germinal center derived lymphoma with 8,500-9,000 new cases/year diagnosed in the US. Despite 90% stage I cHL patients can respond to current systemic therapy, this drops to 60%, when diagnosed in advanced stages. Furthermore, 20-30% of diagnosed patients, would be refractory or would relapse and have a poor prognosis. Refractory and relapsed disease (RRD) is currently the challenge when treating cHL patients. There is no specific therapy to offer rather than rescue chemotherapy schemes, which fails in 50% of the cases and associates with high risk severe toxicity. This highlights the need to deeper understand the cHL molecular biology, the screening for molecular markers suitable to identify the risk of refractory and relapse disease and specific therapeutic directed-targets. We have previously reported that the alternative NFkB pathway, mediated by Rel-B and NIK (NFkB Inducing Kinase), plays an important role in cHL survival. Its constitutive activation sustains high BCL2 expression levels and seems to be involved in the RRD. BCL2 was found as a specific Rel-B target gene in cHL cells by ChIP-Seq (Chromatin Immunoprecipitation sequencing) and expression arrays. BCL2 exogenous expression was enough to partially rescue the death induce in cHL cells, which highlight the relevance of this alternative NFkB pathway target gene. Since the BCL2 data was obtained in human cHL cell lines established from patients with refractory and relapsed disease, we decided to analyze whether mediators of this pathway and BCL2 could be useful as prognosis markers and would represent potential targetable factors in both refractory and relapsed disease. We analyzed NIK and BCL2 citoplasm expression in Hodgkin Reed-Sternberg cells (HRS) in the lymph node biopsies of 113 cHL naïve of therapy patients by inmunohistochemistry [52 female Md age and (range) 36 (6-88), 61 male 40.7 (9-78)]. The follow-up period range from 6 to 136 months. The univariate analysis showed no correlation between NIK or BCL2 expression and the prognosis clinical and pathological parameters, including the PET Scan indicated at the end of the first line treatment, neither the molecular markers routinely assayed. The statistical significance was maintained in multivariate analysis (Logistic and Cox Regression p=0.01). NIK expression did not associate with prognosis but the BCL2 expression level correlated with lack of response to conventional therapy and both early and late disease progression. The survival analysis, using the Kaplan-Meir curves, showed that patients with ≥60% positive HRS cells had a shorter disease-free survival (DFS) [Log Rank Test (Mantel Cox) p=0.002] and a reduced overall survival (OS) [Log Rank Test (Mantel Cox) p=0.02]. L1236, U-H01, KM-H2, SUPDH1 and L540, human cHL cell lines that express BCL2 protein, were sensitive to venetoclax, a specific BCL2 inhibitor. The drug induced a cell cycle arrest in S-Phase when treated with 1uM each 24 hours during 10 days, as compared to wild type cells and cells treated with the vehicle. In summary, we found that the alternative NFkB pathway plays a role in the refractory and relapsed classic Hodgkin Lymphoma disease, being BCL2 one of its key downstream target genes. BCL2 can be used as a prognosis marker determined by routine immunohistochemistry at diagnosis of the primary disease. BCL2 expression correlated with refractory disease to first line conventional therapy and disease progression. Based on the venetoclax effect in cHL cell lines we believe BCL2 directed-therapy in cHL should be considered in the subgroup of cHL patients that express this protein in ≥60% HRS cells in the lymph node biopsy performed at diagnosis. Disclosures No relevant conflicts of interest to declare. OffLabel Disclosure: venetoclax used to specifically block BCL2.

The IRE1-XBP1s Pathway Impairment Underpins NK Cell Dysfunction in Hodgkin Lymphoma, That Is Partly Restored By PD-1 Blockade

Background The frequent loss of Major Histocompatibility Complex I molecule (MHC-I) on Hodgkin/Reed-Sternberg (HRS)-cells renders them susceptible to Natural Killer (NK) cell-mediated lysis in Hodgkin Lymphoma (HL). Optimal NK cell function involves migration from peripheral blood to sites of disease, formation of an immune synapse (NKIS) between NK cells and HRS cells, and release of effector molecules. We recently showed that PD-1+ NK cells are expanded in the circulation of patients with HL (Vari, F Blood 2018), and that PD-1 blockade enhances their anti-HRS capabilities. However, mechanisms behind the functional impairment of NK cells in HL patients and the impact PD-1 blockade has on NK cell function remain to be established. Although the IRE1-XBP1s pathway, part of the unfolded protein response (UPR) system, has established and fundamental roles in macrophage, B, T and dendritic cells homeostatic function, its involvement in NK cells remains unknown. We hypothesized that IRE1-XBP1s dysfunction contributes to NK cell impairment and tested the impact of PD-1 blockade on individual components of NK cell function, including migration, NKIS formation, and cytokine release. Methods Ex-vivo functional assays were performed on blood from 20 participants. Confocal microscopy, time-lapse imaging, trans-well migration, and functional in-vitro immune assays were utilized on a range of NK and HRS cell lines, with and without IRE1-XBP1s small molecule inhibitors (4µ8c and 6-bromo) and/or PD-1 blockade (pembrolizumab). Results Stimulation of both NK cell lines and primary NK cells, with HRS lines resulted in marked and rapid IRE1-XBP1s pathway activation. This occurred independently of the canonical UPR and was associated with increased NK cell effector function. However, IRE1-XBP1s pathway inhibition resulted in aberrant NK cell morphology, reduced motility and migration, deficient NKIS formation and impaired interferon-gamma (IFNγ) and tumor necrosis factor alpha (TNFα) release. Next, we tested the IRE1-XBP1s pathway in the pre-therapy blood of patients with HL and compared this with healthy age/gender matched controls. Strikingly, following co-culture with an HRS-line the pathway was not activated, but this abnormality was restricted to the CD56brightCD16-ve subset that we have previously shown to be expanded and enriched in PD-1 (as well as downregulation of the lymphoid migratory chemokine CCR7) in patients with HL. In subsequent experiments using in-vitro expanded populations of primary NK cells from HL patients, IRE1-XBP1s pathway inhibition impaired the migration, NKIS formation, CD107a degranulation, and secretion of IFNγ and TNFα. Effects were partially but not completely restored by addition of PD-1 blockade (Fig 1). Conclusion Here, we outline a hitherto unrecognized mechanism involving the IRE1-XBP1s pathway that is pivotal to NK cell function, including the relatively poorly understood processes of migration, NKIS formation, and cytokine secretion. Notably, IRE1-XBP1s pathway activation is dysfunctional within the PD-1 enriched CD56brightCD16- NK cell subset. Although PD-1 blockade appears to have a multi-faceted beneficial role on NK cell migrational/NKIS and cytokine release capabilities, it is still only capable of partial restoration of NK cell effector function. Further understanding of the pathways operative in NK cells may result in improved immunotherapeutic strategies to enhance this arm of the immune response in patients with HL. Disclosures Gandhi: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Research Funding; Roche: Honoraria, Other: Travel Support; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Evaluation of the Functional Landscape of Systemic Immunity in Classical Hodgkin Using a Novel Single Cell Platform (Isolight)

Background: Classical Hodgkin lymphoma (HL) has a unique histopathology, with rare malignant Hodgkin/Reed Sternberg (HRS) cells surrounded by a strong inflammatory cellular component in the tumor microenvironment (TME). Although extensive studies describe the interdependence of the HRS cells and the TME, the impact of HL on systemic immunity has not been well described. Here, we develop a new approach, employing a recently commercialized single cell cytokine secretion platform (IsoLight) to assess, precisely and comprehensively, the function of peripheral blood mononuclear cells (PBMCs) in HL patients. Methods: Cells were selected from 4 HL patients: 2 newly diagnosed who had a complete response (CR) to therapy standard first line therapy, and 2 relapsed patients who progressed on second line chemotherapy (PD). Cryopreserved PBMCs from a pre-treatment and post-treatment time point for each patient were thawed, rested overnight, stimulated with PMA/ionomycin and loaded into the IsoLight single cell cytokine secretion system. IsoLight captures single cells in microwells; as cytokines are secreted, they are bound by antibodies lining the microwell cover. Bound cytokines are then revealed by fluorescent secondary antibodies and photos are taken at various time points to assess fluorescence intensity, which corresponds to the relative amount of each cytokine secreted. Twenty thousand cells can be assayed per sample simultaneously. Results: The percentage of cytokine-secreting cells varied dramatically by donor (12%-48%), with monofunctional cells making only TNFa, MIP1b, or IL-15 dominating the functional landscape. Polyfunctional cells, capable of making three or more cytokines simultaneously represented only 0.1-7% of the cells in each sample, but there were more of these cells, and each secreted higher levels of cytokines, in individuals who responded to therapy with a CR. Responders also secreted higher levels of IL2, Perforin, IL4, IL12, MIP1a, and TNFb (p values ranging from 0.005 to 0.03), and lower levels of IL9 and IL22 (p=0.0028 and 0.021, respectively), compared to non-responders at diagnosis. Responders lost expression of IL4, IL7, and MIP1a over the course of treatment (pre- vs post-treatment, p=0.01 to 0.05), while non-responders gained cells that expressed IL4, IL5, IL10, IL17, and TNFb from diagnosis to end of treatment (p=0.001 to 0.05). Conclusion: This work represents an important methodological advance in immune monitoring for hematologic malignancies. Single cell cytokine secretion technology measures more cytokines simultaneously than flow cytometry, providing a sample-sparing and comprehensive overview of the functional landscape of immune cells in a patient. Moreover, the technology provides cell-by-cell information about cytokine secretion, unlike Luminex. Our work represents the first application of this technology to HL, which we use to define, for the first time, the particular combinations of 32 cytokines that can be secreted by individual immune cells. We also identify candidate cytokines whose frequency at diagnosis may predict treatment outcome, and reveal changes in cytokine levels over treatment time that may distinguish patients destined to relapse. Immunotherapy may impact PBMC function differently, this may partially explain the high efficacy of this therapy in the relapsed population. The impact of immunotherapy on cytokine levels is currently under investigation by our group in a larger study. Other important questions which are under investigation include the impact of prior chemotherapy on cytokine profiles in relapsed patients, and whether certain cytokines which increase during treatment may be a surrogage for tumor bulk in patients with PD. Cytokines elevated in patients with poor responses to treatment include IL9, IL10, IL17, and IL22, which may present attractive drug targets if validated in our larger ongoing follow-up study. Disclosures Diefenbach: Bristol-Myers Squibb: Consultancy, Research Funding; MEI: Research Funding; Denovo: Research Funding; Genentech: Consultancy, Research Funding; Incyte: Research Funding; LAM Therapeutics: Research Funding; Merck: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Trillium: Research Funding; Millenium/Takeda: Research Funding. Hymes:Celgene: Consultancy. Martin:Janssen: Consultancy; Sandoz: Consultancy; Karyopharm: Consultancy; Celgene: Consultancy; Teneobio: Consultancy; I-MAB: Consultancy. Ruan:Celgene: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie company: Research Funding; Juno: Consultancy; Kite: Consultancy. Leonard:Miltenyi: Consultancy; Akcea Therapeutics: Consultancy; Sandoz: Consultancy; AstraZeneca: Consultancy; Bayer Corporation: Consultancy; Epizyme, Inc: Consultancy; BeiGene: Consultancy; Miltenyi: Consultancy; ADC Therapeutics: Consultancy; Akcea Therapeutics: Consultancy; Sandoz: Consultancy; Celgene: Consultancy; Epizyme, Inc: Consultancy; Karyopharm Therapeutics: Consultancy; AstraZeneca: Consultancy; Bayer Corporation: Consultancy; Celgene: Consultancy; Sutro Biopharma: Consultancy; Merck: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Gilead: Consultancy; Karyopharm Therapeutics: Consultancy; Sutro Biopharma: Consultancy; Nordic Nanovector: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy; Gilead: Consultancy; Nordic Nanovector: Consultancy; BeiGene: Consultancy; Merck: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; MorphoSys: Consultancy.

OP-38 - Initial presentation of prostate cancer may hint different clinical characteristics along with serving predictive biomarker in castration-resistant prostate cancer patients treated with abiraterone acetate

Loss of the epigenetic marker 5-hydroxymethylcytosine (5hmC) has been demonstrated in a variety of neoplasms. Several recent studies have shown epigenetic alteration in Classical Hodgkin lymphoma (CHL), which may impact treatment. We demonstrate near universal depletion of 5hmC in the neoplastic Hodgkin Reed-Sternberg (H/RS) cells in all cases of CHL (49/49). We hypothesized that the addition of vitamin C–a cofactor for the ten-eleven translocation (TET) enzymes which oxidize 5-methylcytosine (5mC) to 5hmC - may replenish levels of 5hmC. The CHL cell line L428 was grown in optimal conditions and then subjected to vitamin C treatment, which demonstrated reduced cell viability as well as caspase activation and increased concentration of 5hmC. A more detailed understanding of the epigenetic landscape of CHL may help guide future therapies.

Genotyping circulating tumor DNA of pediatric Hodgkin lymphoma.

We used hybrid capture-targeted next-generation sequencing of circulating cell-free DNA (ccfDNA) of pediatric Hodgkin lymphoma (PHL) patients to determine pathogenic mechanisms and assess the clinical utility of this method. Hodgkin-Reed/Sternberg (HRS) cell-derived single nucleotide variants, insertions/deletions, translocations and VH-DH-JH rearrangements were detected in pretherapy ccfDNA of 72 of 96 patients. Number of variants per patient ranged from 1 to 21 with allele frequencies from 0.6 to 42%. Nine translocation breakpoints were detected. Genes involved in JAK/STAT, NFkB and PI3K signaling and antigen presentation were most frequently affected. SOCS1 variants, mainly deletions, were found in most circulating tumor (ct) DNAs, and seven of the nine translocation breakpoints involved SOCS1. Analysis of VH-DH-JH rearrangements revealed an origin of PHL HRS cells from partially selected germinal center B cells. Amounts of pretherapy ctDNA were correlated with metabolic tumor volumes. Furthermore, in all ccfDNA samples of 43 patients with early response assessment quantitative qPET < 3, indicative of a favorable clinical course, ctDNA was not detectable. In contrast, in five of six patients with qPET > 3, indicative of an unfavorable clinical course, ctDNA remained detectable. ccfDNA analysis of PHL is thus a suitable approach to determine pathogenic mechanisms and monitor therapy response.

Expression of CD47 antigen in Reed-Sternberg cells as a new potential biomarker for classical Hodgkin lymphoma.

CD47 over expression has been reported in several tumor subtypes. CD47 interacts with SIRPalpha on macrophages inhibiting phagocytic signal, providing a survival advantage to tumor. CD47, therefore, represents a valuable target for immunotherapy and is currently under clinical investigation. We aimed to study CD47 expression in Hodgkin Reed Sternberg cells (HRS). We tested a polyclonal CD47 antibody (LifeSpan Biosciences, Seattle, WA) expression along with classical HRS cell markers on a tissue array of 16 classical Hodgkin Lymphoma (CHL) tumor biopsies obtained from newly diagnosed, non-selected patients (8 Female, 8 Male patients) in our institution from October 2016 to January 2018. Histologic subtypes were nodular sclerosis in 11 cases, mixed Cellularity in 3 cases and lymphocyte rich in 2 additional cases. Median age was 53 years (Range: 8, 74). Early stage disease was found in three patients without unfavorable prognostic factors according to EORTC and GHSG criteria, one patient with unfavorable prognostic factors and nine patients had advanced disease. Bulk disease was present in one patient. Normal lymphoid tissue and normal prostate epithelium were used as normal controls as recommended by manufacturer. Approval from the Local Ethical committee was obtained before any analysis. CD47 was overexpressed on all HRS cells with a characteristic dot-like pattern in 13/13 cases of CHL. HRS clearly expressed CD47 more intensely than infiltrating T and stromal cells. We propose that HRS cells, by up-regulating CD47, might avoid innate immunity check on tumor growth, which could be circumvented using blocking monoclonal antibodies.

Abstract 1189: Revisiting immune exhaustion in Hodgkin’s lymphoma

Abstract Clinical successes with immune check-point blockers have demonstrated the potency of the immune system in controlling cancers, most strikingly in Hodgkin lymphoma (HL), where overall response rates to PD1/L1 inhibitors approach 90%. Complete or durable responses, however, are uncommon, therefore targeting the PD1/L1 axis alone is not sufficient. Recent work analyzing the spatial arrangement of PD1 and PDL1 expressing cells has given us new insight into the mechanism of action of PD1/L1 inhibitors, however this work limited itself to studying a single check point marker on a subset of cells. We hypothesize that comprehensive profiling of the frequency and spatial arrangement of immune cells in the Hodgkin lymphoma tumor immune microenvironment (TME) will provide new insights into the mechanism of checkpoint blockers and identify novel targets for immune therapy. Until now, multiparameter spatial analysis of the immune microenvironment was limited by technical challenges. Flow and mass cytometry are able to identify immune subsets of interest but spatial information is lost. Multiplex tissue imaging methods are limited to 6-8 simultaneous markers and cannot capture the full complexity of the immune phenotypes. The Fluidigm Hyperion imaging mass cytometry (IMC) system combines a CyTOF mass cytometer with a laser ablation system allowing for 40+ parameter simultaneous immunophenotyping on a single slide of FFPE tissue, with sub-cellular resolution. We have developed a panel of 34 antibodies that allow for comprehensive characterization of CD4, CD8 and myeloid cells components in the TME of Hodgkin lymphoma using IMC. Here we report on our spatial analysis of TIM3 and LAG3 expressing CD4+ lymphocytes. Our data suggests LAG3+CD4+ and TIM3+CD4+ lymphocytes had shorter mean nearest distance to PDL1+Hodgkin Reed-Sternberg (HRS) cells upon comparison to PDL1- HRS cells (t-test, p=1.703e-08,p=1.126e-14). Future studies should explore multiple exhausted marker models that seeks to further understand the presence of simultaneous exhaustion signals in the niche environment. These data suggest that therapies that target TIM3 and/or LAG3 should be tested in Hodgkin Lymphoma and that spatial analysis of immune subsets by IMC should be explored as selective and pharmacodynamic biomarkers. Citation Format: Anthony R. Colombo, Monirath Hav, Erik Gerdtsson, Jose Bisnesto-Villasboas, Stephen Ansell, James Hicks, Peter Kuhn, Akil Merchant. Revisiting immune exhaustion in Hodgkin’s lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1189.

Abstract 5053: Epstein-Barr virus prevalence in classical Hodgkin lymphoma tumors is explained by histologic subtype, not race/ethnicity in a multiethnic US population

Abstract Epstein-Barr virus (EBV) is present in a varying proportion of classical Hodgkin lymphoma (cHL) tumors reportedly associated with age, sex, race/ethnicity and histologic subtype. As part of a study to examine the tumor microenvironment and survival in a multiethnic set of US cHL cases, we examined the distribution of EBV expression in tumor blocks from a subset of 269 of the available cases. We confirmed cHL diagnosis and histological subtype in H&amp;E sections of FFPE tumor blocks of excisions and core biopsies from cases provided by Southern California Kaiser, Winship Cancer Center at Emory University, City of Hope National Medical Center, Grady Memorial Hosiptal, University of California Los Angeles and University of Southern California hospitals diagnosed from 1996-2016. Immunostain results were available for most cases. Tissue microarrays were constructed with two 2 mm cores from each case with 29 cases on each array. EBER was assessed using in situhybridization and scored as negative, positive in HRS cells or positive in the surrounding normal infiltrate. Demographic and clinical information, including the biopsy anatomic site, subtype, race/ethnicity (Hispanic, African American, Asian, non-Hispanic white), age at diagnosis and gender. Multiple logistic regression was conducted to assess the relationship between age, race/ethnicity, gender, subtype and EBV tumor status. Race/ethnicity data was available at this time for 237 cases. Of these, 186 were nodular sclerosis (NS), 53 were mixed cellularity (MC), 8 were lymphocyte depleted (LD), 3 were lymphocyte rich (LR), and 10 were not otherwise specified (NOS). Fifty-seven cases were African American, 48 were non-Hispanic white, 115 were Hispanic, 16 were Asian and one was other race. 106 were female (42%). Age at diagnosis ranged from 5-84 years, with 118 (50%) in the adolescent/young adult (AYA) range (15-35). EBV prevalence in HRS cells by subtype was 0% for LD, 47% for MC, 33% for LR, 23% for NS and 50% for NOS. When restricted to the two most common subtypes, NS and MC, histologic subtype alone was a statistically significant predictor of EBV tumor status (p=.0008) and when adjusting for age, sex, site and race/ethnicity (p=.0011). In NS cases, EBV HRS cell positivity was highest in non-Hispanic whites (31%), followed by Hispanics (23%) and African Americans (18%). Among MC cases, it was very high among African Americans (80%) compared to Hispanics and non-Hispanic whites (33-39%). The patterns were similar when restricted to the AYA age group. 6.5%, 4% and 20% of EBV-negative NS, MC and NOS cases, respectively, had EBV present in non-malignant lymphocytes but not in HRS cells. Histologic subtype was the strongest predictor of EBV HRS cell positivity in this set of multiethnic cHL patients. Unlike previous reports, EBV-positive tumors were not more common among non-whites, except for African American MC cases. Citation Format: Rachel Bolanos, Amie Hwang, Chun Chao, Christopher Flowers, Sheeja Pullarkat, Jose Aparicio, Sophia Wang, Karen Mann, Leon Bernal-Mizrachi, Joo Song, Christian Steidl, Christine Lee, Wendy Cozen, Iran Siddiqi. Epstein-Barr virus prevalence in classical Hodgkin lymphoma tumors is explained by histologic subtype, not race/ethnicity in a multiethnic US population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5053.

The complementary role of insulin-like growth factor II mRNA-binding protein 3 (IMP3) in diagnosis of Hodgkin's lymphoma

BackgroundHodgkin's Lymphoma (HL) is a peculiar subtype of lymphoid malignancies. The etiology of HL is still unknown. Insulin-like growth factor II mRNA-binding Protein 3 (IMP3) is a member of IMP family. In HL, IMP3 is expressed in the cytoplasmic compartment of the tumor cells (in both HRS cells & LP cells) against completely negative background of non-tumor cells except for residual germinal centers. Materials & MethodsOf 51 cases of Hodgkin's lymphoma (HL) referred to surgical pathology laboratory at oncology center, Mansoura University (OCMU), Egypt. All cases were stained for CD20, CD3, CD15, CD30 and IMP3. Regarding IMP3 antibody, The slides were then incubated with the Anti-IMP3, mouse monoclonal antibody (1:200, clone sc-365640, concentrated, California) that was used as primary antibody for IMP3 detection for 1 hour at room temperature, followed by incubation with the secondary antibody, poly HRP (horseradish peroxidase), conjugate for mouse/rabbit, for 20 minutes. ResultsIMP3 showed cytoplasmic immunoreactivity in 43 (83%) cases while 8 cases were negative. The sensitivity of combined CD30 & CD15, combined CD30 & IMP3, combined CD15 & IMP3 were 96%, 98% and 94% respectively. On the other hand, the sensitivity of CD30, CD15 and IMP3 alone were 92.2%, 68.6% and 84.3% respectively. All 23 studied cases of NSCHL, all the 17 cases of MCCHL, 7 out of 8 cases of LRCHL and the only case of LDCHL had predominant T-lymphocytes in their background. On the other hand, the 2 cases of NLPHL and only case of LRCHL had predominant B-lymphocytes in their background. ConclusionIMP3 is a novel marker that is expressed in large proportion of both types of HL against nearly negative background. It has no significant increase in sensitivity in detection of the tumor cells when combined with CD30. There are insignificant relations between IMP3 expression and different clinicopathological parameters. Further studies about IMP3 on a large scale of cases are required to confirm its mechanistic role in generation of HL.

PB1997 FREQUENCY OF ABERRANT PHENOTYPE AND HISTIOCYTIC MARKER CD163 AND ITS PROGNOSTIC RELATIONSHIP IN A COHORT OF PATIENTS WITH CLASSICAL HODGKIN LYMPHOMA IN THE NATIONAL CANCER INSTITUTE OF MEXICO (INCAN)

Background: Classical Hodgkin lymphoma (CHL) has a good response to treatment, however, approximately 20% of patients present refractoriness or recurrence. Current prognostic scales cannot accurately identify patients with worse prognosis. High macrophage frequency detected by CD68 expression associate with shorter progression-free survival (PFS) in CHL. However, there are no studies on CD163, a more specific marker for macrophages/M2 histiocytes. Aberrant T-cell antigens (TCA) expression in the Reed Sternberg cells (HRS) also correlates with shorter PFS and overall survival (OS). This encourages the identification of biomarkers that predict a poor response to treatment. Aims: To evaluate the frequency of the histiocyte marker CD163 and aberrant TCA expression of CD2, CD3 and CD4 in HRS cells, as well as their prognostic value in CHL. Methods: CHL cases were included from January 2009 to December 2015. Previous hematoxylin-eosin staining and immunohistochemical markers (CD30, CD15, CD20, CD3 and LMP1) were evaluated, then samples of 1 cm in diameter were taken with at least 10 HRS for Tissue microarrays (TMA), and immunohistochemical stains were performed for CD2, CD4, and CD163. Aberrant TCA expression was considered positive when one, two or the three T-cell markers were expressed on at least 20% of HRS cells, and the histiocyte marker CD163 was considered positive at 25% cutoff. Results: 433 CHL cases were diagnosed, 144 cases met the inclusion criteria and were analyzed. CD163 expression was observed in 66 cases while 78 cases were negative, finding correlations between CD163 and lymphopenia <600/mm3 (p = 0.05), serum albumin <3.4 g/dl (p = 0.003); advanced clinical stage (p = 0.002); and extranodal disease (p = 0.003). However, CD163 was not associated with shorter PFS or OS. Aberrant TCA expression in HRS cells was observed in 34 cases (23.6%), having a statistically significant correlation with nodular sclerosis subtype (p = 0.04); leukocytosis ≥ 15,000 / mm3 (p = 0.001); lymphocytosis> 600 / mm3 (p = 0.039); advanced clinical stage (p = 0.023); and tumor size> 10 cm (p = 0.051). Aberrant TCA expression was not associated with worse PFS or OS either. LMP1 expression co-occurred with Epstein Barr virus (EBV) in 59.6% of patients with mixed cellularity and 43.5% with nodular sclerosis subtypes respectively, in univariate analyses LMP1 expression was not associated with lower PFS (p = 0.30). In multivariate analyses, LMP1 expression was a protective factor for not having aberrant TCA expression with an odds ratio [OR] 0.3; 95% confidence interval [CI]: 0.12-0.78, but at the same time LMP1 correlated with high histiocyte frequency determined by CD163.Summary/Conclusion: In this study, the antigens CD163, CD2, CD3, CD4 and LMP1 were not prognostic biomarkers for PFS and OS, however, they can be useful to predict which patients will be more clinically compromised. Although there are few studies about the clinical correlation and aberrant TCA expression in CHL, in this study we observed a high percentage of aberrant TCA expression (23.6%) compared to previous reports (5-8%). Therefore, aberrant TCA expression in HRS cells is not an uncommon event in CHL; and should be distinguished from anaplastic large cell lymphoma, since this can impact treatment and prognosis.

EVITA: PHASE I/II STUDY OF EVEROLIMUS PLUS ITACITINIB IN RELAPSED/REFRACTORY CLASSICAL HODGKIN LYMPHOMA

Introduction: There is an unmet need for patients (pts) with relapsed/refractory classical Hodgkin lymphoma (cHL) who failed or cannot tolerate immune check point inhibitors and brentuximab vedotin (BV). Biology of cHL is characterized by scant Hodgkin Reed Sternberg cells (HRS) within a pro-inflammatory tumor microenvironment (TME). Both HRS and TME are rich with therapeutic targets. One of those is Akt which is constitutively activated in cHL-derived cell lines and its downstream effectors include mTOR substrates. Other promising targets in cHL are components of JAK/STAT pathway as genetic alterations in multiple genes (including STAT3, STAT5B, JAK1, JAK2, PTPN1) have been demonstrated in cHL. In pre-clinical studies, co-treatment of mTOR and JAK inhibitors resulted in synergistic activity against the proliferation of JAK mutated cell lines. Everolimus (oral inhibitor of mTOR) is clinically active in cHL with overall response rate (ORR) 40%, but low complete response rate (CR) of 5%. Ruxolitinib (oral JAK1/2 inhibitor) monotherapy produced only modest responses in cHL. Itacitinib adipate is another oral JAK inhibitor with potent selectivity for JAK1, but limited data in cHL. Itacitinib also inhibits STAT protein phosphorylation and pro-inflammatory cytokines including IL-6 which is expressed on HRS/TME and its expression has been associated with B symptoms. To our knowledge, no clinical studies have been done with concurrent mTOR/JAK inhibition in cHL. We hypothesize that targeting multiple pathways in HRS/TME using combination of everolimus and itacitinib will result in deeper disease control compared to everolimus monotherapy. Methods: An open-label, single-group study of everolimus in combination with itacitinib is currently opened at the University of Pennsylvania. Eligible pts must have relapsed/refractory cHL after at least 2 prior systemic therapies and must have relapsed after or be ineligible for autologous stem cell transplant. They also must have progressed after treatment with, be intolerant to, or are not a candidate for BV and pembrolizumab/nivolumab. Phase I will evaluate the safety and tolerability of the combination using a standard 3 + 3 design with dose-escalation or de-escalation. The starting dose of everolimus is 5 mg daily and of itacitinib is 300 mg daily with treatment planned for 2 years or until progression/intolerance. Phase II will evaluate the efficacy of the combination in cHL as demonstrated by CR (the null hypothesis is set at CR rate of 5%). Secondary objectives include progression free/overall survival, ORR, duration of response. Exploratory analyses include impact on quality of life/B symptoms. Ancillary studies exploring tumor biology/biomarkers are planned. Since opening in January 2019, 2 pts have been enrolled. The goal is to enroll 23 pts over a period of 3 years. Keywords: Hodgkin lymphoma (HL); JAK/STAT; mTor inhibitors. Disclosures: Nasta, S: Research Funding: Incyte.

Epstein–Barr virus-encoded LMP1 induces ectopic CD137 expression on Hodgkin and Reed–Sternberg cells via the PI3K-AKT-mTOR pathway

CD137 is a potent co-stimulatory molecule on activated T cells, and its ligand (CD137L) is expressed on antigen presenting cells (APC). Ectopic expression of CD137 has been identified on Hodgkin Reed–Sternberg (HRS) cells, the malignant cells in Hodgkin Lymphoma (HL), and CD137 on HRS cells was found to support growth of HRS cells and escape from immune surveillance. HRS cells are mostly derived from B cells, which poses the question of how B cells acquire ectopic CD137 expression during the transformation process. HL is associated with Epstein–Barr virus (EBV) infection. We show that the EBV latent membrane protein 1 (LMP1) induces expression of CD137 in HRS cell lines. In a HL tissue microarray, 96% of the CD137-positive HL cases stained positive for LMP1. LMP1 utilizes the PI3K-AKT-mTOR pathway for inducing CD137 expression. These findings support the role of EBV in HL pathogenesis.

Lenolidamide and IL-15 enhance natural killer cell-mediated immunity and augments the anti-tumor effect of an anti-CD30/CD16A bispecific antibody against Hodgkin’s lymphoma B-cells

Abstract Hodgkin’s lymphoma (HL) is characterized by malignant CD30+ Reed-Sternberg (HRS) B-cells surrounded by an ineffective infiltrate of inflammatory immune cells. T-helper and T-regulatory cells presumably provide survival signals for HRS cells; rescuing them from immune-surveillance by CD8+ cytotoxic T lymphocytes and natural killer (NK) cells, which are also functionally anergic. Clinically, ≈10–30% of HL patients resulted in relapse after front line therapy; highlighting the need for development of new treatments. We investigated a novel bispecific CD16axCD30 antibody, AFM13 (Affimed Therapeutics, AG), which engages NK cells and recruits them towards CD30+ tumor cells. Safety of single-agent AFM13 has been demonstrated in a phase I clinical study, however, disease remission was observed in only 23% of patients. We hypothesized that combining AFM13 with another agent whose safety profile is already been established in HL and also activates NK cells (lenalidomide) could potentially increase anti-tumor efficacy of AFM13. We observed increased expression of CD107a, CD69, CD25 and IFNγ (activation markers) in NK cells isolated from HL patients (HL-NK), that were stimulated ex vivo with IL- 15 + lenalidomide. Pre-treatment with IL-2/IL-15 antibody has been shown to activate and restore T/NK cell cytolytic function. In line with this, IL-15+lenalidomide-stimulated HL-NK cells showed functional restoration by inducing specific lysis of human CD30+ lymphoma cells (30.55±1.49%) in a co-culture assay. While, AFM13 is being investigated in combination with anti-PD1 antibody therapy (NCT02665650), our preclinical data provides the rationale for an AFM13 + Len combination regimen for HL and potentially other CD30+ malignancies.

How Epstein-Barr Virus “Manipulates” The Tumoral Microenvironment in Hodgkin Lymphoma?

Abstract The Epstein-Barr virus (EBV) is a gamma-herpesvirus that colonizes the B-cell system of its human host, allowing it to persist asymptomatically in the majority of the world’s adult population. In most people primary infection goes unnoticed, whereas in a minority of individuals, primary infection results in infectious mononucleosis (IM), a benign condition that almost always resolves after several weeks or months. However, EBV is also causally linked with a number of malignancies, including B-cell lymphomas, such as classical Hodgkin lymphoma (cHL). A proportion of patients with cHL harbor EBV within their tumor cells. Emerging evidence suggests that while EBV is able to subvert cellular processes to promote the growth and survival of HRS cells or their progenitors, mutations in key cell signalization pathways are probably required to do this when EBV is absent. The challenge is to unravel exactly how EBV and its latent genes contribute to the pathogenesis of cHL particularly with respect to how the virus co-operates with cellular genetic and epigenetic changes to drive transformation. It is hoped that the development of better in vitro and in vivo models of disease will reveal more fundamental aspects of EBV’s role in Hodgkin lymphoma pathogenesis and pave the way for targeted therapies for patients with EBV-positive cHL.

Hypoxia-related carbonic anhydrase IX expression is associated with unfavourable response to first-line therapyin classical Hodgkin's lymphoma.

The present study evaluates the impact of hypoxia-related carbonic anhydrase IX and XII isoenzyme expression as a basic adaptive mechanism to neutralise intracellular acidosis in classical Hodgkin's lymphoma (cHL). Eighty-one primary biopsies and 15 relapsed tissue samples diagnosed with cHL were analysed for necrosis, CAIX and CAXII expression and cell proliferation to compare hypoxia-related histological and functional data with survival characteristics. Variable, but highly selective cell membrane CAIX expression could be demonstrated in Hodgkin-Reed-Sternberg (HRS) cells in 39 of 81 samples (48.1%), while virtually no staining presented in their microenvironment. In contrast, CAXII expression in HRS cells could be demonstrated in only 18 of 77 samples (23.4%), with significant stromal positivity (50 of 77, 64.9%). The CAIX+ positive phenotype was strongly associated with lymphocyte depletion (four of four, 100%) and nodular sclerosis (29 of 51, 56.9%) subtypes. CAIX/Ki-67 dual immunohistochemistry demonstrated suppressed cell proliferation in CAIX+ positive compared to CAIX- negative HRS cells (P<0.001). Seventy-two months' progression-free survival (PFS) was significantly lower for the CAIX positive group (0.192) compared with the CAIX negative group (0.771) (P<0.001), while the overall survival (OS) did not differ (P=0.097). Hypoxic stress-related adaptation - highlighted by CAIX expression - results in cellular quiescence in HRS cells, potentially contributing to the short-term failure of the standard chemotherapy in cHL.

Prognostic Significance of IL-6 in Hodgkin Lymphoma

Elevated serum interleukin-6 (IL-6) in Hodgkin lymphoma (HL) is reported to correlate with B symptoms, response rate and survival in adult patients. The authors studied prognostic significance of IL-6 expression by immunohistochemistry on Hodgkin-Reed Sternberg cells and background reactive cells in a retrospective cohort of pediatric HL patients treated with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) from January 2009 through December 2013. Of 142 patients, tissue blocks were retrieved in 110 patients. On logistic regression analysis, IL-6 expression on background cells alone was among the factors associated with inferior response rate (OR-9.9, 95%CI-1.2, 78.3; p = 0.03). On multivariate analysis, IL-6 expression on background cells alone had significant impact on 5 y freedom from treatment failure (FFTF) (HR-7.7, 95% CI-1.2, 48.6; p = 0.03). IL-6 expression by immunohistochemistry in the background cells is an independent poor predictor of response and FFTF in pediatric HL. Further prospective studies in children are needed to confirm the current findings and whether IL-6 expression can be used to stratify treatment.

Primary diagnosis of classic Hodgkin lymphoma by bone marrow aspirate and trephine – an unusual presentation with interesting morphology

An 82-year-old gentleman presented with breathlessness and a 3-month history of fevers and night sweats. Past history was remarkable for an unprovoked pulmonary embolism (PE) 10 months prior for which he had 6 months anticoagulation therapy with no specific malignancy diagnosed at that time. Further inpatient investigations revealed a recurrent PE and a subsequent positron emission tomography/computed tomography (PET/CT) scan showed retrocaval lymphadenopathy with fludeoxyglucose (FDG) avid nodes above and below the diaphragm with spleen, liver and marrow involvement. Staging bone marrow aspirate and trephine (BMAT) demonstrated large bilobed Hodgkin Reed-Sternberg (HRS) cells with lymphocyte rosetting. Trephine histology showed focal collections of large HRS cells with an accompanying inflammatory cell infiltrate. The HRS cells were CD15+/CD30+/PAX5(weak) on immunohistochemistry (IHC). A diagnosis of Classic Hodgkin Lymphoma (CHL) was established based on the marrow findings. Hodgkin lymphoma (HL) with bone marrow (BM) involvement is a relatively infrequent finding (∼5% cases of HL)1,2 and the presence of HRS cells in BM aspirate is rare. This case illustrates an unusual clinical presentation of CHL with primary diagnosis attained by BM biopsy. The patient was commenced on chlorambucil, procarbazine, prednisolone and vinblastine (Ch1VPP) chemotherapy and restaging PET/CT after 6 cycles showed marked interval improvement of FDG avid disease.

Targeting Cancer Cells and Tumor Microenvironment in Preclinical and Clinical Models of Hodgkin Lymphoma Using the Dual PI3Kδ/γ Inhibitor RP6530.

Tumor-associated macrophages (TAMs) and the hyperactivation of the PI3K/AKT pathway are involved in the pathogenesis of Hodgkin lymphoma and affect disease outcome. Because the δ and γ isoforms of PI3K are overexpressed in Hodgkin/Reed-Sternberg (HRS) cells and the tumor microenvironment (TME), we propose that the PI3Kδ/γ inhibitor RP6530 might affect both HRS cells and TME, ultimately leading to an enhanced antitumor response. Hodgkin lymphoma cell lines (L-540, KM-H2, and L-428) and primary human macrophages were used to investigate the activity of RP6530 in vitro and in vivo in Hodgkin lymphoma cell line xenografts. In vitro, RP6530 besides killing and inhibiting the proliferation of Hodgkin lymphoma cells, downregulated lactic acid metabolism, switching the activation of macrophages from an immunosuppressive M2-like phenotype to a more inflammatory M1-like state. By RNA sequencing, we define tumor glycolysis as a specific PI3Kδ/γ-dependent pathway implicated in the metabolic reprogramming of cancer cells. We identify the metabolic regulator pyruvate kinase M2 as the main mediator of tumor-induced immunosuppressive phenotype of macrophages. Furthermore, we show in human tumor xenografts that RP6530 repolarizes TAMs into proinflammatory macrophages and inhibits tumor vasculature, leading to tumor regression. Interestingly, patients with Hodgkin lymphoma experiencing objective responses (complete response and partial response) in a phase I trial using RP6530 showed a significant inhibition of circulating myeloid-derived suppressor cells and an average mean reduction in serum thymus and activation-regulated chemokine levels of 40% (range, 4%-76%). Our results support PI3Kδ/γ inhibition as a novel therapeutic strategy that targets both malignant cells and the TME to treat patients with Hodgkin lymphoma.

Epstein-Barr virus LMP2A utilizes Syk and PI3K to activate NF-κB in B-cell lymphomas to increase MIP-1α production.

The incidence of Hodgkin's lymphoma (HL) is growing due to an increase in Epstein-Barr virus (EBV)-associated HL in AIDS patients. The HL tumor microenvironment is vital for the survival of the malignant Hodgkin-Reed Sternberg (HRS) cells of HL, which express the EBV protein latent membrane protein 2A (LMP2A). While previous work shows that LMP2A mimics B-cell receptor (BCR) signaling to promote the survival of HRS cells, the ability of LMP2A to establish and maintain the tumor microenvironment through the production of chemokines remains unknown. Since BCR signaling induces the production of the chemokine macrophage inflammatory protein-1α (MIP-1α), and since LMP2A is a BCR mimic, we hypothesized that LMP2A increases MIP-1α levels. A comparison of multiple LMP2A-negative and -positive cell lines demonstrates that LMP2A increases MIP-1α. Additionally, LMP2A-mutant cell lines and pharmacologic inhibitors indicate that LMP2A activates a Syk/PI3K/NF-κB pathway to enhance MIP-1α. Finally, based on the finding that an NF-κB inhibitor decreased MIP-1α RNA/protein in LMP2A-positive cells, we are the first to demonstrate that LMP2A increases the nuclear localization of the NF-κB p65 subunit using DNA-binding assays and confocal microscopy in human B cells. These findings not only have implications for the treatment of HL, but also other LMP2A-expressing B-cell tumors that overexpress NF-κB.

Immune targeting of the microenvironment in classical Hodgkin's lymphoma: insights for the hematologist.

While up to 80% of patients with Hodgkin’s lymphoma (HL) are cured with first-line therapy, relapsed/refractory (R/R) disease remains a clinical challenge and is fatal for many young patients. HL is unique in that the tumor cells (Hodgkin Reed–Sternberg; HRS cells) are a small fraction (<1%) of the tumor bulk, with the remaining tumor composed of the cells of the tumor microenvironment (TME). The support and integrity of the TME is necessary for HRS cell growth and survival. Targeting the programmed death 1 pathway has shown exciting activity in relapsed HL and led to United States Food and Drug Administration approval of the checkpoint inhibitors, nivolumab and pembrolizumab, for R/R HL. Novel combinations with checkpoint blockade therapy (CBT), targeted approaches such as combinations of CBT with brentuximab vedotin or chemotherapy, chimeric antigen receptor T-cells, and the use of CBT to potentially sensitize to subsequent therapy are being investigated as treatment approaches. As understanding of the HL TME grows, hopefully this will increase the number of rational therapeutic targets.