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Clostridium perfringens is an anaerobic toxin-producing bacterium associated with intestinal diseases, particularly in neonatal humans and animals. Infant gut microbiome studies have recently indicated a link between C. perfringens and the preterm infant disease necrotizing enterocolitis (NEC), with specific NEC cases associated with overabundant C. perfringens termed C. perfringens-associated NEC (CPA-NEC). In the present study, we carried out whole-genome sequencing of 272 C. perfringens isolates from 70 infants across 5 hospitals in the United Kingdom. In this retrospective analysis, we performed in-depth genomic analyses (virulence profiling, strain tracking and plasmid analysis) and experimentally characterized pathogenic traits of 31 strains, including 4 from CPA-NEC patients. We found that the gene encoding toxin perfringolysin O, pfoA, was largely deficient in a human-derived hypovirulent lineage, as well as certain colonization factors, in contrast to typical pfoA-encoding virulent lineages. We determined that infant-associated pfoA+ strains caused significantly more cellular damage than pfoA− strains in vitro, and further confirmed this virulence trait in vivo using an oral-challenge C57BL/6 murine model. These findings suggest both the importance of pfoA+C. perfringens as a gut pathogen in preterm infants and areas for further investigation, including potential intervention and therapeutic strategies.

Angiogenesis is inhibited in PyMT-BO1 tumours upon NRP1 and NRP2 depletion

Establishing commensal dysbiosis, defined as an inflammatory gut microbiome with low biodiversity, before breast tumor initiation, enhances early dissemination of hormone receptor–positive (HR+) mammary tumor cells. Here, we sought to determine whether cellular changes occurring in normal mammary tissues, before tumor initiation and in response to dysbiosis, enhanced dissemination of HR+ tumors. Commensal dysbiosis increased both the frequency and profibrogenicity of mast cells in normal, non–tumor-bearing mammary tissues, a phenotypic change that persisted after tumor implantation. Pharmacological and adoptive transfer approaches demonstrated that profibrogenic mammary tissue mast cells from dysbiotic animals were sufficient to enhance dissemination of HR+ tumor cells. Using archival HR+ patient samples, we determined that enhanced collagen levels in tumor-adjacent mammary tissue positively correlated with mast cell abundance and HR+ breast cancer recurrence. Together, these data demonstrate that mast cells programmed by commensal dysbiosis activate mammary tissue fibroblasts and orchestrate early dissemination of HR+ breast tumors.

Supplementary Figure from Reciprocal Interactions Between the Gut Microbiome and Mammary Tissue Mast Cells Promote Metastatic Dissemination of HR+ Breast Tumors

Neuropilin (NRP) expression is highly correlated with poor outcome in multiple cancer subtypes. As known coreceptors for VEGFRs, core drivers of angiogenesis, past investigations have alluded to their functional roles in facilitating tumorigenesis by promoting invasive vessel growth. Despite this, it remains unclear as to whether NRP1 and NRP2 act in a synergistic manner to enhance pathologic angiogenesis. Here we demonstrate, using NRP1ECKO, NRP2ECKO, and NRP1/NRP2ECKO mouse models, that maximum inhibition of primary tumor development and angiogenesis is achieved when both endothelial NRP1 and NRP2 are targeted simultaneously. Metastasis and secondary site angiogenesis were also significantly inhibited in NRP1/NRP2ECKO animals. Mechanistic studies revealed that codepleting NRP1 and NRP2 in mouse-microvascular endothelial cells stimulates rapid shuttling of VEGFR-2 to Rab7+ endosomes for proteosomal degradation. Our results highlight the importance of targeting both NRP1 and NRP2 to modulate tumor angiogenesis.Significance:The findings presented in this study demonstrate that tumor angiogenesis and growth can be arrested completely by cotargeting endothelial NRP1 and NRP2. We provide new insight into the mechanisms of action regulating NRP-dependent tumor angiogenesis and signpost a novel approach to halt tumor progression.

Co-targeting NRP1 and NRP2 inhibits tumour growth and angiogenesis

Integrin beta3 antagonist treatment on tumor cells and BMMs in culture

Anti-CSF1 treatment on β3KOM mice

Blood vessel density analysis of tumor tissue

Supplementary methods and figure legends

Flow cytometric analysis of leukocyte infiltration in tumor tissue

Antibody list for FACS

The differentially expressed genes (DEG) lists

STAT1 and STAT6 downstream gene expression

Integrin β3 is critical for tumor invasion, neoangiogenesis, and inflammation, making it a promising cancer target. However, preclinical and clinical data of integrin β3 antagonists have demonstrated no benefit or worse outcomes. We hypothesized that integrin β3 could affect tumor immunity and evaluated tumors in mice with deletion of integrin β3 in macrophage lineage cells (β3KOM). β3KOM mice had increased melanoma and breast cancer growth with increased tumor-promoting M2 macrophages and decreased CD8+ T cells. Integrin β3 antagonist, cilengitide, also enhanced tumor growth and increased M2 function. We uncovered a negative feedback loop in M2 myeloid cells, wherein integrin β3 signaling favored STAT1 activation, an M1-polarizing signal, and suppressed M2-polarizing STAT6 activation. Finally, disruption of CD8+ T cells, macrophages, or macrophage integrin β3 signaling blocked the tumor-promoting effects of integrin β3 antagonism. These results suggest that effects of integrin β3 therapies on immune cells should be considered to improve outcomes. Cancer Res; 76(12); 3484–95. ©2016 AACR.

LPS treatment enhances integrin beta3 ligand binding

Primers for qPCR

The percentage of infiltrating immune cells in B16 tumor tissue

Integrin beta3 antagonist treatment on early stage breast tumor growth

Integrin beta3 regulates STAT6 signaling

Integrin gene expression of WT and Itgb3-/- BMMs after M1 or M2 polarization

Establishing commensal dysbiosis, defined as an inflammatory gut microbiome with low biodiversity, before breast tumor initiation, enhances early dissemination of hormone receptor–positive (HR+) mammary tumor cells. Here, we sought to determine whether cellular changes occurring in normal mammary tissues, before tumor initiation and in response to dysbiosis, enhanced dissemination of HR+ tumors. Commensal dysbiosis increased both the frequency and profibrogenicity of mast cells in normal, non–tumor-bearing mammary tissues, a phenotypic change that persisted after tumor implantation. Pharmacological and adoptive transfer approaches demonstrated that profibrogenic mammary tissue mast cells from dysbiotic animals were sufficient to enhance dissemination of HR+ tumor cells. Using archival HR+ patient samples, we determined that enhanced collagen levels in tumor-adjacent mammary tissue positively correlated with mast cell abundance and HR+ breast cancer recurrence. Together, these data demonstrate that mast cells programmed by commensal dysbiosis activate mammary tissue fibroblasts and orchestrate early dissemination of HR+ breast tumors.

The ability to study the role of specific genes in endothelial cell biology is made possible by our ability to modulate their expression through siRNA or knockout technologies. However, many in vitro protocols, particularly those of a biochemical nature, require large numbers of endothelial cells. These types of analyses are encumbered by the need to repeatedly produce and characterize primary endothelial cell cultures and can be greatly facilitated by the use of immortalized microvascular endothelial cells. However, we have found that the manipulation of gene expression in these cells is not always straight forward. Here we describe how we alter gene expression in polyoma middle T antigen immortalized microvascular endothelial cells isolated from wild-type and genetically modified mice to study the role of cell adhesion molecules in downstream assays.

Indications for autologous (auto-HCT) and allogeneic transplantation (allo-HCT) in relapsed/refractory Hodgkin lymphoma (rrHL) have been long established. The expectation is that long-term outcomes have significantly improved over time with increased experience in these procedures. The objective of this study was to assess whether this is the case and to identify further areas of improvement. A total of 13,639 adult patients receiving an auto-HCT or allo-HCT for rrHL were reported to the European Society for Blood and Marrow Transplantation (EBMT) over a 25-year period. Regarding auto-HCT, recipients are younger, interval between diagnosis and transplant shorter, peripheral blood has become the universal stem cell source and the use of total body irradiation is almost non-existent in recent years. Allo-HCT is currently mostly used as a second transplant; recipients are younger, fitter and less frequently, chemorefractory. Reduced intensity conditioning protocols have vastly replaced myeloablative protocols. Increasing numbers of haplo-HCT have been reported. Both in auto-HCT and allo-HCT, NRM, PFS and OS have significantly improved but relapse remains the main cause of treatment failure. A better selection of patients and improvements in the supportive care has resulted in a reduction in the NRM. Relapse after HCT remains unchanged and further research is needed.

Establishing commensal dysbiosis, defined as an inflammatory gut microbiome with low biodiversity, prior to breast tumor initiation, enhances early dissemination of hormone-receptor positive (HR+) mammary tumor cells. Here, we sought to define mammary tissue mediators of dysbiosis-induced tumor dissemination. We found that commensal dysbiosis increased both the frequency and profibrogenicity of mast cells in the mammary tissue, a phenotypic change that persisted after tumor implantation. Fibroblast activation and tissue remodeling associate with enhanced breast tumor metastasis. We employed pharmacological and adoptive transfer approaches to demonstrate that mammary tissue mast cells from dysbiotic animals enhances dissemination of HR+ tumor cells. Collagen levels in mammary tissues from HR+ breast cancer patients correlated with mast cell abundance, suggesting clinical relevance of mast cell-mediated fibroblast activation. Together, these data demonstrate that a gut-mast cell axis exists that induces fibroblast activation and orchestrates early dissemination of HR+ breast tumors.SignificanceOur study defines the mechanism by which an inflammatory gut microbiome facilitates HR+ breast tumor cell dissemination. We establish that gut commensal dysbiosis triggers mammary tissue mast cells to facilitate early metastatic dissemination. These findings highlight a novel gut microbiome-innate immune cell axis involved in negative breast cancer outcomes.

The ability to form a variety of cell-matrix connections is crucial for angiogenesis to take place. Without stable anchorage to the extracellular matrix (ECM), endothelial cells (ECs) are unable to sense, integrate and disseminate growth factor stimulated responses that drive growth of a vascular bed. Neuropilin-2 (NRP2) is a widely expressed membrane-bound multifunctional non-tyrosine kinase receptor, which has previously been implicated in influencing cell adhesion and migration by interacting with α5-integrin and regulating adhesion turnover. α5-integrin, and its ECM ligand fibronectin (FN) are both known to be upregulated during the formation of neo-vasculature. Despite being descriptively annotated as a candidate biomarker for aggressive cancer phenotypes, the EC-specific roles for NRP2 during developmental and pathological angiogenesis remain unexplored. The data reported here support a model whereby NRP2 actively promotes EC adhesion and migration by regulating dynamic cytoskeletal remodeling and by stimulating Rab11-dependent recycling of α5-integrin-p-FAK complexes to newly assembling adhesion sites. Furthermore, temporal depletion of EC-NRP2 in vivo impairs primary tumor growth by disrupting vessel formation. We also demonstrate that EC-NRP2 is required for normal postnatal retinal vascular development, specifically by regulating cell-matrix adhesion. Upon loss of endothelial NRP2, vascular outgrowth from the optic nerve during superficial plexus formation is disrupted, likely due to reduced FAK phosphorylation within sprouting tip cells.

Measurable residual disease (MRD) prior to hematopoietic cell transplant (HCT) for acute myeloid leukemia (AML) in first complete morphological remission (CR1) is an independent predictor of outcome, but few studies address CR2. This analysis by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation registry assessed HCT outcomes by declared MRD status in a cohort of 1042 adult patients with AML CR2 at HCT. Patients were transplanted 2006–2016 from human leukocyte antigen (HLA) matched siblings (n = 719) or HLA 10/10 matched unrelated donors (n = 293). Conditioning was myeloablative (n = 610) or reduced-intensity (n = 432) and 566 patients (54%) had in-vivo T cell depletion. At HCT, 749 patients (72%) were MRD negative (MRD NEG) and 293 (28%) were MRD positive (MRD POS). Time from diagnosis to HCT was longer in MRD NEG than MRD POS patients (18 vs. 16 months (P P P = 0.001), but there was no difference in terms of overall survival. Prognostic factors for relapse and LFS were MRD NEG status, good risk cytogenetics, and longer time from diagnosis to HCT. In-vivo T cell depletion predicted relapse.

The ability to form a variety of cell-matrix connections is crucial for angiogenesis to take place. Without stable anchorage to the extracellular matrix (ECM), endothelial cells (ECs) are unable to sense, integrate and disseminate growth factor stimulated responses that drive growth of a vascular bed. Neuropilin-2 (NRP2) is a widely expressed membrane-bound multifunctional non-tyrosine kinase receptor, that has previously been implicated in influencing cell adhesion and migration by interacting with α5-integrin and regulating adhesion turnover. α5-integrin, and its ECM ligand fibronectin (FN) are both known to be upregulated during the formation of neo-vasculature. Despite being descriptively annotated as a candidate biomarker for aggressive cancer phenotypes, the EC-specific roles for NRP2 during developmental and pathological angiogenesis remain unexplored. The data reported here support a model whereby NRP2 actively promotes EC adhesion and migration by regulating dynamic cytoskeletal remodelling and by stimulating Rab11-dependent recycling of α5-integrin-p-FAK complexes to newly assembling adhesion sites. Furthermore, temporal depletion of EC-NRP2in vivoimpairs primary tumour growth by disrupting vessel formation. We also demonstrate that EC-NRP2 is required for normal postnatal retinal vascular development, specifically by regulating cell-matrix adhesion. Upon loss of endothelial NRP2, vascular outgrowth from the optic nerve during superficial plexus formation is disrupted, likely due to reduced FAK phosphorylation within sprouting tip cells.

Published data describing the efficacy and safety of autologous stem-cell transplantation (autoSCT) in post-transplant lymphoproliferative disorders (PTLD) is limited to case reports. This is a retrospective analysis of 21 patients reported to the EBMT registry who received an autoSCT for PTLD post solid organ transplant (SOT). Median age at autoSCT was 47 (range: 22–71) years. The commonest SOTs were kidney (48%) and liver (24%). Commonest histologies included DLBCL-type PTLD (14/21) and plasmacytoma-like PTLD (3/21). Patients received a median of two lines of therapy (range: 1–4) pre-autoSCT. ECOG performance status pre-autoSCT was 0 in 14% and 1 in 86%. Remission status pre-autoSCT was CR 47% and PR 38%. BEAM conditioning was used in 57% and high-dose melphalan in 10%. The median follow-up post-autoSCT was 64 months for alive patients. 3-year PFS was 62% [95% confidence interval (CI) 44–87%] and 3-year OS was 61% [95% CI:43–86]. There were 12 deaths, including four related to autoSCT. 100-day non-relapse-mortality (NRM) was 14% and 1-year NRM was 24%. This study suggests that autoSCT, although feasible and with potential therapeutic activity, is associated with a high NRM, primarily driven by infectious toxicity. A multi-disciplinary approach, expert microbiological input and stringent patient selection are required to optimise outcomes., SCOPUS: ar.j, info:eu-repo/semantics/published

There is emerging evidence that resident microbiota communities, that is, the microbiota, play a key role in cancer outcomes and anticancer responses. Although this has been relatively well studied in colorectal cancer and melanoma, other cancers, such as breast cancer (BrCa), have been largely overlooked to date. Importantly, many of the environmental factors associated with BrCa incidence and progression are also known to impact the microbiota, for example, diet and antibiotics. Here, we explore BrCa risk factors from large epidemiology studies and microbiota associations, and more recent studies that have directly profiled BrCa patients' gut microbiotas. We also discuss how in vivo studies have begun to unravel the immune mechanisms whereby the microbiota may influence BrCa responses, and finally we examine how diet and specific nutrients are also linked to BrCa outcomes. We also consider future research avenues and important considerations with respect to study design and implementation, and we highlight some of the important unresolved questions, which currently limit our overall understanding of the mechanisms underpinning microbiota‐BrCa responses.

Acute graft-versus-host disease (aGvHD) remains a major threat to successful outcome following allogeneic hematopoietic cell transplantation though advances in prophylaxis and supportive care have been made. The aim of this study is to test whether the incidence and mortality of aGvHD have decreased over time. 102,557 patients with a median age of 47.6 years and with malignancies after first allogeneic sibling or unrelated donor (URD) transplant were studied in the following periods: 1990-1995, 1996-2000, 2001-2005, 2006-2010 and 2011-2015. Findings: 100-day incidences of aGvHD grades II-IV decreased from 40% to 38%, 32%, 29% and 28%, respectively, over calendar time (P

Angiogenesis relies on the ability of endothelial cells (ECs) to migrate over the extracellular matrix via integrin receptors to respond to an angiogenic stimulus. Of the two neuropilin (NRP) orthologs to be identified, both have been reported to be expressed on normal blood and lymphatic ECs, and to play roles in the formation of blood and lymphatic vascular networks during angiogenesis. Whilst the role of NRP1 and its interactions with integrins during angiogenesis has been widely studied, the role of NRP2 in ECs is poorly understood. Here we demonstrate that NRP2 promotes Rac-1 mediated EC adhesion and migration over fibronectin (FN) matrices in a mechanistically distinct fashion to NRP1, showing no dependence on β3 integrin (ITGB3) expression, or VEGF stimulation. Furthermore, we highlight evidence of a regulatory crosstalk between NRP2 and α5 integrin (ITGA5) in ECs, with NRP2 depletion eliciting an upregulation of ITGA5 expression and disruptions in ITGA5 cellular organisation. Finally, we propose a mechanism whereby NRP2 promotes ITGA5 recycling in ECs; NRP2 depleted ECs were found to exhibit reduced levels of total ITGA5 subunit recycling compared to wild-type (WT) ECs. Our findings expose NRP2 as a novel angiogenic player by promoting ITGA5-mediated EC adhesion and migration on FN.

ADAMTS-1 is an extracellular protease with critical roles in organogenesis and angiogenesis. Here we demonstrate a functional convergence of ADAMTS-1 and the transmembrane heparan sulfate proteoglycan syndecan-4 in influencing adhesion, migration and angiogenesis. Knockdown of ADAMTS-1 in endothelial cells resulted in a parallel reduction in cell surface syndecan-4, attributable to increased matrix metalloproteinase-9 (MMP9) activity. Knockdown of either ADAMTS-1 or syndecan-4 increased cellular responses to vascular endothelial growth factor A isoform VEGFA164, and increased ex vivo aortic ring microvessel sprouting. On fibronectin, knockdown of either protein enhanced migration and promoted formation of long α5 integrin-containing fibrillar adhesions. However, integrin α5 null cells still showed increased migration in response to ADAMTS-1 and syndecan-4 siRNA treatment. Plating of naïve endothelial cells on cell-conditioned matrix from ADAMTS-1 and syndecan-4 knockdown cells demonstrated that the altered adhesive behaviour was matrix dependent, and this correlated with a lack of expression of fibulin-1: an extracellular matrix co-factor for ADAMTS-1 that is known to inhibit migration. These findings support the notion that ADAMTS-1 and syndecan-4 are functionally interconnected in regulating cell migration and angiogenesis, via collaboration with MMP9 and fibulin-1. This article has an associated First Person interview with the first author of the paper., Summary: ADAMTS-1 and syndecan-4 collaborate to regulate cell adhesion, migration and integrin α5 trafficking, and to sequester VEGFA164, inhibiting angiogenesis.

The diverse community of commensal microbes that comprise the gut microbiota is known to play an integral role in human health, not least through its ability to regulate host immune responses and metabolic pathways. Alterations to the homeostasis of this community, including through the use of broad-spectrum antibiotics, have already been associated with the progression of several cancers, namely melanoma and liver. The aggressive nature of breast cancer (BrCa), largely due to its ability to metastasize early, has ranked the disease with the second highest mortality rate of all cancers globally. Yet the body of research into the complex relationship between the microbiota and BrCa is still limited. This study found that a depletion of the microbiota, through the administration of antibiotics, significantly increased the rate of primary tumour progression in mouse BrCa models. We show that antibiotic-induced microbiota disturbances lead to changes in behaviour of a relatively obscure tumour-immune cell population: mast cells. We observed increases in tumour stroma-associated mast cells in antibiotic treated animals. Moreover, inhibition of mast cell degranulation, via cromolyn, slowed tumour progression in antibiotic treated animals but not in control animals. Thus, it appears that a perturbed microbiota drives stroma-associated mast cell recruitment and activation, which in turn promotes primary tumour growth through an as yet unknown mechanism.One Sentence Summary:We show that breast cancer progression is accelerated through a unique/novel immune response involving mast cells as a result of an antibiotic induced perturbation of the gut microbiota in a mouse model.

The impact of measurable residual disease (MRD) on cord blood transplantation (CBT) outcomes has remained debated. To address this issue, we assessed the impact of measurable MRD at CBT on outcomes in large cohort of patients with acute leukemia. Inclusion criteria included adult patients with acute myeloid (AML) or acute lymphoblastic leukemia (ALL), CBT as first allo-HCT in first or second complete remission (CR) at transplantation, and known MRD status at the time of CBT. Data from 506 patients were included in the analysis. Among them, 317 patients had AML and 189 had ALL. Positive MRD was reported in 169 (33%) patients while the remaining 337 patients were MRD negative at CBT. At 2 years, relapse incidence was 18% in patients with MRD negativity vs 33% in those with MRD positivity at transplantation (P

Haploidentical stem cell transplantation (haploSCT) is becoming a major transplant modality for lymphoma. To assess the effects of donor characteristics, stem cell source and conditioning on outcomes, we identified 474 adults with Hodgkin (HL; 240), peripheral T-cell (PTCL; 88), diffuse large B-cell (77), mantle cell (40) or follicular lymphoma (FL; 29), who received haploSCT with post-transplant cyclophosphamide. Median follow-up of alive patients was 32 months. On multivariate analysis, acute graft-versus-host disease (GVHD) grade 2-4 was lower with offspring donors or bone marrow cells, whereas extensive chronic GVHD was higher in partial response at haploSCT or when using sisters, haploidentical donors beyond first degree, or female donors in male patients. Progression-free survival (PFS) was better for FL, HL and PTCL, whereas overall survival (OS) was better for HL and PTCL. Complete remission at haploSCT improved PFS and OS whereas these were negatively affected by cytomegalovirus donor positive/recipient positive status. No other donor characteristics (age, gender, human leucocyte antigen mismatch, ABO incompatibility) affected PFS or OS except use of haploidentical donors beyond first degree, which negatively affected OS. PFS and OS are mostly influenced by disease status and lymphoma subtype, supporting the use of any first degree haploidentical family member as a donor.

BACKGROUND: The treatment of patients with Hodgkin lymphoma (HL) who develop disease progression after undergoing allogeneic stem cell transplantation (allo‐SCT) remains challenging. METHODS: The authors assessed outcomes in 184 adult patients with HL who developed disease recurrence or progression after a matched related or unrelated allo‐SCT at European Society for Blood and Marrow Transplantation–participating centers between 2010 and 2014. RESULTS: Eighty patients who received brentuximab vedotin (BV) salvage therapy were compared with 104 patients who did not. Patients in the BV group were younger (median age of 30 years vs 34 years) and were more likely to receive pretransplant BV (65% vs 46%) or posttransplant donor lymphocyte infusion (66% vs 33%). The 2 groups otherwise were comparable. Patients in the BV group received a median of 6 doses of posttransplant BV, resulting in a complete remission rate of 29%, a partial response rate of 45%, and a stable disease rate of 26%. Response to BV after allo‐SCT did not appear to be affected by receipt of pretransplant BV. Despite a longer median follow‐up for surviving patients in the BV group (33 months vs 23 months; P

Background Allogeneic hematopoietic stem cell transplantation (allo-HCT) remains the only potentially curative treatment option for relapsed follicular lymphoma (FL), yet questions remain about the optimal timing. This study analyzed long-term outcomes and associated factors among recipients of allo-HCT with FL. Methods Patients with relapsed FL who underwent allo-HCT from 2001 to 2011 with a human leukocyte antigen (HLA)-matched donor were included. Outcome analyses for overall survival (OS), progression-free survival (PFS), transplant-related mortality (TRM), and disease relapse/progression were calculated. A multivariate analysis was performed to determine factors associated with outcomes, and a prognostic score for treatment failure was developed in a subset analysis of patients. Results In all, 1567 patients with relapsed FL were included; the median follow-up was 55 months. The 5-year probabilities of OS and PFS were 61% and 52%, respectively. The 5-year cumulative incidences of disease progression/relapse and TRM were 29% and 19%, respectively. Chemoresistant disease, older age, heavy pretreatment, poor performance status (PS), and myeloablative protocols were predictors for worse survival. The prognostic score, using age, lines of prior therapy, disease status, and PS, stratified patients into 3 groups-low, intermediate, and high risk-with 5-year PFS rates of 68%, 53%, and 46%, respectively, and 5-year OS rates of 80%, 62%, and 50%, respectively. Conclusions Allo-HCT should be considered for patients with relapsed FL and available HLA-matched donors. Outcomes are better in earlier phases of the disease, and reduced-intensity conditioning should be preferred. The prognostic score presented here can assist in counseling patients and determining the time to proceed to transplantation. Cancer 2018;124:1733-42. © 2018 American Cancer Society.

Improvements in the understanding of the metabolic cross-talk between cancer and its microenvironment are expected to lead to novel therapeutic approaches. Acute myeloid leukemia (AML) cells have increased mitochondria compared with nonmalignant CD34+ hematopoietic progenitor cells. Furthermore, contrary to the Warburg hypothesis, AML relies on oxidative phosphorylation to generate adenosine triphosphate. Here we report that in human AML, NOX2 generates superoxide, which stimulates bone marrow stromal cells (BMSC) to AML blast transfer of mitochondria through AML-derived tunneling nanotubes. Moreover, inhibition of NOX2 was able to prevent mitochondrial transfer, increase AML apoptosis, and improve NSG AML mouse survival. Although mitochondrial transfer from BMSC to nonmalignant CD34+ cells occurs in response to oxidative stress, NOX2 inhibition had no detectable effect on nonmalignant CD34+ cell survival. Taken together, we identify tumor-specific dependence on NOX2-driven mitochondrial transfer as a novel therapeutic strategy in AML.

Plerixafor is a CXC chemokine receptor (CXCR4) antagonist that mobilizes stem cells in the peripheral blood. It is indicated (in combination with granulocyte-colony stimulating factor [G-CSF]) to enhance the harvest of adequate quantities of cluster differentiation (CD) 34+ cells for autologous transplantation in patients with lymphoma or multiple myeloma whose cells mobilize poorly. Strategies for use include delayed re-mobilization after a failed mobilization attempt with G-CSF, and rescue or pre-emptive mobilization in patients in whom mobilization with G-CSF is likely to fail. Pre-emptive use has the advantage that it avoids the need to re-schedule the transplant procedure, with its attendant inconvenience, quality-of-life issues for the patient and cost of additional admissions to the transplant unit. UK experience from 2 major centers suggests that pre-emptive plerixafor is associated with an incremental drug cost of less than £2000 when averaged over all patients undergoing peripheral blood stem cell (PBSC) transplant. A CD34+ cell count of

Salvage chemotherapy and autologous stem cell transplantation (auto-SCT) results in the cure of around 50% of patients with Hodgkin lymphoma (HL) failing first line therapy. In historical data, patients who progressed after auto-SCT had a poor outcome, with a median overall survival (OS) of around 1-2 years. Significant progress has been achieved in the last decade with the use of brentuximab vedotin (BV) or check-point inhibitors (CPI) and the increasing use of haploidentical transplant. However, little information is available about the characteristics and real-world outcomes of patients with HL relapsing after auto-SCT in the current era. To assess prognosis of patients with recurrent-HL post auto-SCT over time, we analyzed the European Blood and Marrow Transplant registry data of 1781 adult HL patients who relapsed between 2006 and 2017 after a first auto-SCT. A specific questionnaire was sent to all participant centers to obtain additional data regarding characteristics of the patients, treatment of relapse and outcome after auto-SCT failure. Detailed data were collected for 760 patients [median age 32; interquartile range (IQR) 25-42] included in this study. After a median follow-up for alive patients of 57 months (IQR: 29-89), the 4-year OS after relapse for the 760 included patients was 46% (95%CI: 43-50) and similar to that of 1021 non-included patients (45%, 95%CI: 41-48). The 4-year OS after relapse continuously increased from 35% (95%CI: 27-45) for 136 patients relapsing in 2006-2008, to 43% (95%CI: 37-49) for 258 patients relapsing in 2009-2011, 49% (95%CI: 43-56) for 238 patients relapsing in 2012-2014, and 61% (95%CI: 52-72) for 128 patients relapsing in 2015-2017 (p=0.001) (Figure 1). Improvement over time was predominantly noted in patients who had an early relapse (within 12 months) after auto-SCT (p=0.01) but not in those with a late relapse (p=0.6). On multivariate analysis, patients who relapsed in more recent years and those with a longer interval from transplant to relapse had a better OS, whereas increasing age, poor performance status at relapse, bulky disease at relapse, extranodal disease at relapse and presence of B-symptoms at relapse were associated with a worse OS. Regarding treatment at relapse, BV was used in 233 patients (31%) after a median of 2 months from relapse (IQR: 0.8-8), predominantly as first treatment of relapse (155 patients). BV use increased over the 4 time periods from 3% to 19%, 49% and 49% respectively, and resulted in a complete remission (CR) in 46% and a partial response (PR) in 32%. The 4-year OS from BV use for relapse after auto-SCT was 56% (95%CI: 49-64). CPI were used in 91 patients (12%) including nivolumab in 75 patients and pembrolizumab in 12 patients after a median of 18 months from relapse (IQR: 5-35). CPI use increased over the 4 time periods from 1% to 4%, 14% and 35% respectively, and resulted in a CR of 44%, PR 32%, with a 4-year OS from CPI use of 44% (95%CI: 30-63). Finally, a second SCT (SCT2) was performed in 330 patients (43%) predominantly allogeneic SCT (285 patients, 86%) including a haploidentical SCT in 54 patients (16%). SCT2 was performed in 40% and 37% of patients relapsing in 2006-2008 and 2009-2011 respectively but its use increased to 49% and 51% of patients relapsing in 2012-2014 and 2015-2017 respectively. Four-year OS after SCT2 was 55%. In conclusion, outcome after post-transplant relapse has improved significantly in recent years, particularly in the case of early relapse, possibly reflecting, among other factors, the efficacy of post-transplant salvage including BV, CPI and second transplant. These large-scale real-world data can serve as benchmark for future studies in that setting. Figure 1 Disclosures Blaise: Jazz Pharmaceuticals: Honoraria. Sureda Balari:Incyte: Consultancy; Celgene: Consultancy, Honoraria; BMS: Speakers Bureau; Roche: Honoraria; Sanofi: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Gilead/Kite: Consultancy, Honoraria; Merck Sharpe and Dohme: Consultancy, Honoraria, Speakers Bureau; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria.

Around half of patients with Hodgkin Lymphoma (HL) who progress or relapse through first line therapy can be cured with salvage chemotherapy followed by autologous stem cell transplant (ASCT). However, this leaves approximately 50% of patients that will relapse after ASCT. The pivotal phase II SG035-00303 trial demonstrated that these patients can be successfully treated with Brentuximab Vedotin (BV), and a proportion of them can be long term free of disease without any further intervention. The objective of the current study was to investigate whether these findings were borne out in the real world via interrogation of the EBMT registry. We retrospectively analysed data for 101 patients with HL who had BV as their first treatment for relapse after ASCT from 2012 to 2019. The median age at ASCT was 34 years (range: 19-65), 60% being male and with 62% being in complete response (CR) at the time of ASCT. Carmustine, Etoposide, Cytarabine and Melphalan (BEAM) was the most common conditioning regimen, having been employed in 72% of the cases. The median time from ASCT to relapse was 10.1 months (interquartile range (IQR): 6.1-25.1). The median time on BV was 3.4 months (IQR: 2.1-5.24). BV treatment resulted in a best overall response rate (ORR) of 59% with a CR rate of 37%. At last follow-up only 2 patients remain on treatment with BV. The main reason for discontinuation of BV was progression which occurred in 37% of the patients. In 32 cases (33%) the treatment was stopped electively to proceed to a second transplant, and overall nearly a quarter (22%) completed the full treatment course. Only 5% of patients stopped due to toxicity (peripheral neuropathy 2 and neutropenia, infusion reaction and other, 1 each). Further therapy was given after BV in over half of evaluable patients (58%), with check point inhibitors (CPIs) being the most common agents used (24% of these). Nearly two thirds (64/101) of the patients received a second transplant, which were nearly all allogeneic stem cell transplant (alloSCT, 59/64), and most of these (49/59) with reduced intensity conditioning (RIC). 26% of the alloSCT recipients experienced grade II-IV acute graft versus host disease (GvHD) and 25% developed chronic GvHD. At last follow up, 62% of all patients were alive with a median follow-up of 25 months after starting BV. Of these, 27 had received a second transplant, who were mostly in CR at last follow up (26/27) and a further 22 had relapsed. There were 11 patients of the 63 still alive who continued to be responding to BV without further therapy with a median duration of response of 30 months. In conclusion BV use for relapse after ASCT was well tolerated generally, with only a minority of patients stopping treatment due to toxicity. However, although almost two thirds of the patients achieved a response, further treatment was often needed after BV, notably with CPIs and most patients were consolidated with a RIC alloSCT. These results confirm that only a minority of patients can achieve a durable remission with BV alone. Disclosures Brice: Takeda France: Consultancy, Honoraria; Millennium Takeda: Research Funding; BMS: Honoraria. Blaise:Molmed: Consultancy, Honoraria; Jazz Pharmaceuticals: Honoraria; Sanofi: Honoraria; Pierre Fabre medicaments: Honoraria. Stamatoullas:Celgene: Honoraria; Takeda: Consultancy. Robak:Takeda: Consultancy, Research Funding; UCB: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel grant, Research Funding; Amgen: Consultancy, Other: Travel grant; Roche: Consultancy, Other: Travel grant, Research Funding; Abbvie: Consultancy, Honoraria, Other: Travel grant, Research Funding; Gilead: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Acerta: Research Funding; Morphosys AG: Research Funding. Wahlin:Roche and Gilead: Consultancy.

Angiogenesis relies on the ability of endothelial cells (ECs) to migrate over the extracellular matrix via integrin receptors to respond to an angiogenic stimulus. Of the two neuropilin (NRP) orthologs to be identified, both have been reported to be expressed on normal blood and lymphatic ECs, and to play roles in the formation of blood and lymphatic vascular networks during angiogenesis. Whilst the role of NRP1 and its interactions with integrins during angiogenesis has been widely studied, the role of NRP2 in ECs is poorly understood. Here we demonstrate that NRP2 promotes Rac-1 mediated EC adhesion and migration over fibronectin (FN) matrices in a mechanistically distinct fashion to NRP1, showing no dependence on β3 integrin (ITGB3) expression, or VEGF stimulation. Furthermore, we highlight evidence of a regulatory crosstalk between NRP2 and α5 integrin (ITGA5) in ECs, with NRP2 depletion eliciting an upregulation of ITGA5 expression and disruptions in ITGA5 cellular organisation. Finally, we propose a mechanism whereby NRP2 promotes ITGA5 recycling in ECs; NRP2 depleted ECs were found to exhibit reduced levels of total ITGA5 subunit recycling compared to wild-type (WT) ECs. Our findings expose NRP2 as a novel angiogenic player by promoting ITGA5-mediated EC adhesion and migration on FN.