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NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pediatric Aggressive Mature B-Cell Lymphomas include recommendations for the diagnosis and management of pediatric patients with primary mediastinal large B-cell lymphoma (PMBL) and sporadic variants of Burkitt lymphoma and diffuse large B-cell lymphoma. PMBL is now considered as a distinct entity arising from mature thymic B-cells accounting for 2% of mature B-cell lymphomas in children and adolescents. This discussion section includes the recommendations outlined in the NCCN Guidelines for the diagnosis and management of pediatric patients with PMBL.

Osteosarcoma (OS) is a genetically diverse bone cancer that lacks a consistent targetable mutation. Recent studies suggest the IGF/PI3K/mTOR pathway and YAP/TAZ paralogs regulate cell fate and proliferation in response to biomechanical cues within the tumor microenvironment. How this occurs and their implication upon osteosarcoma survival, remains poorly understood. Here, we show that IGF-1R can translocate into the nucleus, where it may act as part of a transcription factor complex. To explore the relationship between YAP/TAZ and total and nuclear phosphorylated IGF-1R (pIGF-1R), we evaluated sequential tumor sections from a 37-patient tissue microarray by confocal microscopy. Next, we examined the relationship between stained markers, clinical disease characteristics, and patient outcomes. The nuclear to cytoplasmic ratios (N:C ratio) of YAP and TAZ strongly correlated with nuclear pIGF-1R (r = 0.522

Pediatric acute myeloid leukemia (AML) is a rare disease that is profoundly heterogeneous at a molecular and clinical level. Although, in recent clinical trials, the 5-year event-free survival rates for childhood AML ranged between 49% and 64%, bone marrow relapse still occurs in up to one-third of cases. New therapies are required to continue progress in this aggressive hematological disease. Optimistically, we anticipate that the next challenge may be not a lack of appropriate therapies but an abundance of potentially effective strategies and a question of how best to incorporate them into pediatric clinical practice.The focus of this review is to highlight all promising agents currently under investigation for pediatric AML, including nucleoside analogs, epigenetic modifiers, targeted small-molecule inhibitors, monoclonal antibodies, novel chemotherapeutics, and immunotherapies.While AML outcomes have improved over time for pediatric AML patients, our challenge is how to improve outcomes with our new knowledge of genetic and epigenetic aberrations. We posit to incorporate active therapy options into combination strategies and utilize targeted and immunotherapy approaches, as more opportunities are available.

Relapsed or refractory pediatric patients with B-acute lymphoblastic leukemia (B-ALL) have high rates of toxicities and relapse, and novel therapy is needed. We present a case of a 5-year-old male child with high-risk B-ALL that was refractory to several re-induction regimens. He was put into minimal residual disease-negative remission after re-induction with chemotherapy plus overlapping rituximab, inotuzumab ozogamicin, and blinatumomab, termed mini-hyper-CVD (cyclophosphamide, vincristine, and dexamethasone) plus CRIB (condensed rituximab, inotuzumab ozogamicin, and blinatumomab). This regimen was well tolerated, and he received his transplant and engrafted with no significant infections, toxicities, or sinusoidal obstruction syndrome. This is the first reported use of a condensed sequential immunotherapy/chemotherapy regimen in a pediatric leukemia patient.

Like several other translocation-positive sarcomas, Ewing sarcoma (ES) exists exclusively in a high-grade, undifferentiated state. We believe that the pathognomonic EWS-FLI1 fusion protein (FP) responsible for ES is intimately linked to cell fate, differentiation, and plasticity. Over the last two decades, an emerging body of research has begun the challenging task of deciphering how the FP - via its action as an aberrant transcription factor- blocks differentiation and promotes reprogramming toward a quasi-stem-like cell with features of neuroectodermal or mesenchymal stem cells. We compared ES transcriptome data to other cancers in an unsupervised comparison between the gene expression profile of cancer cells in the Cancer Cell Line Encyclopedia (CCLE) and tumor expression datasets. While ES is traditionally classified as a bone cancer, it does not cluster near other bone cancer subtypes (e.g., osteosarcomas) or soft-tissue sarcomas. To that end, we sought to better understand how targeting the FP affected ES differentiation and lineage. Using a CRISPR knockout (CRISPR-KO) model of A673, we targeted Exon 4 of the EWSR1 protein in the n-terminus of the FP and generated a clonal pool (EWSR1 CRISPR KO). We used single-cell RNA sequencing (scRNA-seq) to identify the transcriptional changes after FP knockout (FP KO). We identified five cell clusters in the data. We observed the expression of FP target genes (EWS-FLI1 On), PRKCB, and LIPI and saw robust expression in four of the clusters suggesting normal FP expression. Conversely, FP repressed genes (EWS-FLI1 Off), LOX and IGFBP3, were elevated in cluster 2, which contained only EWSR1 CRISPR KO cells. This suggests that the FP was successfully knocked out in cluster 2 (FP EWSR1 KO). Next, we asked how the FP KO changed the lineage/fate of A673 cells. We hypothesized that loss of the FP would induce mesenchymal/fibroblastic fate in ES cells. To answer this, we used SingleR, which compares the gene expression profile of query cells to the CCLE data set, to identify the nearest cell type. Interestingly, all clusters except the FP EWSR1 KO cluster identified closely with ES and related tumors. The FP EWSR1 KO cluster, which expressed EWS-FLI1 ‘off’ genes, did not resemble ES. Using a granular identification with cell lines, we confirmed that the highest score was A673 since these were A673 cell lines. However, the FP EWSR1 KO resulted in a phenotype unrelated to A673 and more closely resembled cell lines with fibroblastic phenotype. Our data suggest that targeting the FP significantly changed ES lineage. While the FP KO did not lead to cell death, our results suggest a novel gene regulatory network acts to sustain ES lineage. Further perturbations in this network may lead to a better understanding of ES treatment, particularly as novel EWS-FLI1-directed therapies emerge. Citation Format: Danh Truong, Sandhya Krishnan, Alexandar Lazar, David McCall, Joseph A. Ludwig. Understanding Ewing sarcoma cell fate. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3559.

Cancer immunotherapies are associated with remarkable therapeutic response rates but also with unique and severe toxicities, which potentially result in rapid deterioration in health. The number of clinical applications for novel immune effector-cell therapies, including chimeric antigen receptor (CAR)-expressing cells, and other immunotherapies, such as immune-checkpoint inhibitors, is increasing. In this Consensus Statement, members of the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Hematopoietic Cell Transplantation-Cancer Immunotherapy (HCT-CI) Subgroup, Paediatric Diseases Working Party (PDWP) of the European Society of Blood and Marrow Transplantation (EBMT), Supportive Care Committee of the Pediatric Transplantation and Cellular Therapy Consortium (PTCTC) and MD Anderson Cancer Center CAR T Cell Therapy-Associated Toxicity (CARTOX) Program collaborated to provide updated comprehensive recommendations for the care of children, adolescents and young adults receiving cancer immunotherapies. With these recommendations, we address emerging toxicity mitigation strategies, we advocate for the characterization of baseline organ function according to age and discipline-specific criteria, we recommend early critical care assessment when indicated, with consideration of reversibility of underlying pathology (instead of organ failure scores) to guide critical care interventions, and we call for researchers, regulatory agencies and sponsors to support and facilitate early inclusion of young patients with cancer in well-designed clinical trials.

Osteosarcoma (OS) is a molecularly heterogeneous, aggressive, poorly differentiated pediatric bone cancer that frequently spreads to the lung. Relatively little is known about phenotypic and epigenetic changes that promote lung metastases. To identify key drivers of metastasis, we studied human CCH-OS-D OS cells within a previously described rat acellular lung (ACL) model that preserves the native lung architecture, extracellular matrix, and capillary network. This system identified a subset of cells—termed derived circulating tumor cells (dCTCs)—that can migrate, intravasate, and spread within a bioreactor-perfused capillary network. Remarkably, dCTCs highly expressed epithelial-to-mesenchymal transition (EMT)-associated transcription factors (EMT-TFs), such as ZEB1, TWIST, and SOX9, which suggests that they undergo cellular reprogramming toward a less differentiated state by coopting the same epigenetic machinery used by carcinomas. Since YAP/TAZ and AXL tightly regulate the fate and plasticity of normal mesenchymal cells in response to microenvironmental cues, we explored whether these proteins contributed to OS metastatic potential using an isogenic pair of human OS cell lines that differ in AXL expression. We show that AXL inhibition significantly reduced the number of MG63.2 pulmonary metastases in murine models. Collectively, we present a laboratory-based method to detect and characterize a pure population of dCTCs, which provides a unique opportunity to study how OS cell fate and differentiation contributes to metastatic potential. Though the important step of clinical validation remains, our identification of AXL, ZEB1, and TWIST upregulation raises the tantalizing prospect that EMT-TF-directed therapies might expand the arsenal of therapies used to combat advanced-stage OS.

Relapsed or refractive pediatric B-Acute Lymphoblastic Leukemia (B-ALL) patients have high rates of toxicities and relapse, and novel therapy is needed. We present a case of a 5-year-old male with high-risk B-ALL that was refractive to several re-induction regimens. He was put into MRD-negative remission after re-induction with chemotherapy plus overlapping rituximab, inotuzumab ozogamicin and blinatumomab, termed Mini-Hyper-CVD plus CRIB. This was well tolerated, and he received his transplant and engrafted with no significant infections, toxicities, or sinusoidal obstruction syndrome. This is the first reported use in pediatrics of a condensed sequential immunotherapy/chemotherapy regimen in a pediatric leukemia patient.

Desmoplastic small round cell tumor (DSRCT) is an aggressive, usually incurable sarcoma subtype that predominantly occurs in post-pubertal young males. Recent evidence suggests that the androgen receptor (AR) can promote tumor progression in DSRCTs. However, the mechanism of AR-induced oncogenic stimulation remains undetermined. Herein, we demonstrate that enzalutamide and AR-directed antisense oligonucleotides (AR-ASO) block 5α-dihydrotestosterone (DHT)-induced DSRCT cell proliferation and reduce xenograft tumor burden. Gene expression analysis and chromatin immunoprecipitation sequencing (ChIP-seq) were performed to elucidate how AR signaling regulates cellular epigenetic programs. Remarkably, ChIP-seq revealed novel DSRCT-specific AR DNA binding sites adjacent to key oncogenic regulators, including WT1 (the C-terminal partner of the pathognomonic fusion protein) and FOXF1. Additionally, AR occupied enhancer sites that regulate the Wnt pathway, neural differentiation, and embryonic organ development, implicating AR in dysfunctional cell lineage commitment. Our findings have immediate clinical implications given the widespread availability of FDA-approved androgen-targeted agents used for prostate cancer.ONE SENTENCE SUMMARYWe demonstrate that DSRCT, an aggressive pediatric cancer, is an AR-driven malignancy capable of responding to androgen deprivation therapy.

The BCL-2 inhibitor venetoclax improves survival for adult patients with acute myeloid leukemia (AML) in combination with lower-intensity therapies, but its benefit in pediatric patients with AML remains unclear. We retrospectively reviewed two Texas Medical Center institutions’ experience with venetoclax in 43 pediatric patients with AML; median age 17 years (range, 0.6–21). This population was highly refractory; 44% of patients (n = 19) had ≥3 prior lines of therapy, 37% (n = 16) had received a prior bone marrow transplant, and 81% (n = 35) had unfavorable genetics KMT2A (n = 17), WT1 (n = 13), FLT3-ITD (n = 10), monosomy 7 (n = 5), TP53 (n = 3), Inv(3) (n = 3), IDH1/2 (n = 2), monosomy 5 (n = 1), NUP98 (n = 1) and ASXL1 (n = 1). The majority (86%) received venetoclax with a hypomethylating agent. Grade 3 or 4 adverse events included febrile neutropenia in 37% (n = 16), non-febrile neutropenia in 12% (n = 5), anemia in 14% (n = 6), and thrombocytopenia in 14% (n = 6). Of 40 patients evaluable for response, 10 patients (25%) achieved complete response (CR), 6 patients (15%) achieved CR with incomplete blood count recovery (CRi), and 2 patients (5%) had a partial response, (CR/CRi composite = 40%; ORR = 45%). Eleven (25%) patients received a hematopoietic stem cell transplant following venetoclax combination therapy, and six remain alive (median follow-up time 33.6 months). Median event-free survival and overall survival duration was 3.7 months and 8.7 months, respectively. Our findings suggest that in pediatric patients with AML, venetoclax is well-tolerated, with a safety profile similar to that in adults. More studies are needed to establish an optimal venetoclax-based regimen for the pediatric population.

Current in vitro methods for assessing cancer biology and therapeutic response rely heavily on monolayer cell culture on hard, plastic surfaces that do not recapitulate essential elements of the tumor microenvironment. While a host of tumor models exist, most are not engineered to control the physical properties of the microenvironment and thus may not reflect the effects of mechanotransduction on tumor biology. Utilizing coaxial electrospinning, we developed three-dimensional (3D) tumor models with tunable mechanical properties in order to elucidate the effects of substrate stiffness and tissue architecture in osteosarcoma. Mechanical properties of coaxial electrospun meshes were characterized with a series of macroscale testing with uniaxial tensile testing and microscale testing utilizing atomic force microscopy on single fibers. Calculated moduli in our models ranged over three orders of magnitude in both macroscale and microscale testing. Osteosarcoma cells responded to decreasing substrate stiffness in 3D environments by increasing nuclear localization of Hippo pathway effectors, YAP and TAZ, while downregulating total YAP. Additionally, a downregulation of the IGF-1R/mTOR axis, the target of recent clinical trials in sarcoma, was observed in 3D models and heralded increased resistance to combination chemotherapy and IGF-1R/mTOR targeted agents compared to monolayer controls. In this study, we highlight the necessity of incorporating mechanical cues in cancer biology investigation and the complexity in mechanotransduction as a confluence of stiffness and culture architecture. Our models provide a versatile, mechanically variable substrate on which to study the effects of physical cues on the pathogenesis of tumors. STATEMENT OF SIGNIFICANCE: The tumor microenvironment plays a critical role in cancer pathogenesis. In this work, we engineered 3D, mechanically tunable, coaxial electrospun environments to determine the roles of the mechanical environment on osteosarcoma cell phenotype, morphology, and therapeutic response. We characterize the effects of varying macroscale and microscale stiffnesses in 3D environments on the localization and expression of the mechanoresponsive proteins, YAP and TAZ, and evaluate IGF-1R/mTOR pathway activation, a target of recent clinical trials in sarcoma. Increased nuclear YAP/TAZ was observed as stiffness in 3D was decreased. Downregulation of the IGF-1R/mTOR cascade in all 3D environments was observed. Our study highlights the complexity of mechanotransduction in 3D culture and represents a step towards controlling microenvironmental elements in in vitro cancer investigations.

Chimeric antigen receptor (CAR) therapies such as tisagenlecleucel, indicated for children and young adults with relapsed and/or refractory CD19+ acute lymphoblastic leukemia (ALL), have been associated with striking treatment outcomes and overall survival. Yet, they are also associated with unique and potentially life-threatening complications. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity (ICANS) are generally reversible complications of CAR therapies, but many patients may require critical care support especially if they are not promptly recognized and appropriately managed by frontline healthcare staff. As CAR therapies become more widely available, it is important that inter-professional staff members be aware of general principles regarding diagnosis and management. We hypothesized that an inter-professional education (IPE) simulation-based education intervention (CAR-TEAM) would improve knowledge base and confidence regarding complications of CAR therapies among inter-professional staff. Here, we demonstrate that following CAR-TEAM training, >90% of participants demonstrated knowledge proficiency and confidence in the IPE content area. CAR-TEAM training may serve as an important tool to establish initial and continued competency among sites introducing CAR therapies.

BACKGROUND: Children with isolated neutropenia (absolute neutrophil count [ANC] METHODS: We performed a 5.5-year institutional review board–approved retrospective chart review of children referred to our pediatric hematology and oncology clinics for isolated neutropenia. Neutropenia was categorized as mild (ANC of 1001–1500/μL), moderate (ANC of 500–1000 μL), severe (ANC of 201–500/μL), or very severe (ANC of ≤200/μL). RESULTS: Among 155 children referred with isolated neutropenia, 45 (29%) had mild neutropenia, 65 (42%) had moderate neutropenia, 30 (19%) had severe neutropenia, and 15 (10%) had very severe neutropenia. Only 29 (19%) children changed to an ANC category lower than their initial referral category. At a median follow-up of 12 months, 101 children had resolution of neutropenia, 40 children had mild neutropenia, 10 children had moderate neutropenia, 3 children had severe neutropenia, and 1 patient had very severe neutropenia. A specific diagnosis was not identified in most (54%) children. The most common etiologies were viral suppression (16%), autoimmune neutropenia (14%), and drug-induced neutropenia (8%). Black children had a 3.5 higher odds of having persistent mild neutropenia. Six (4%) children received granulocyte colony-stimulating factor therapy. CONCLUSIONS: Most children referred for isolated neutropenia do not progress in severity and do not require subspecialty interventions or hospitalizations.

Advances in genomic, transcriptomic and epigenomic profiling now identifies pediatric ependymoma as a defined biological entity. Molecular interrogation has segregated these tumors into distinct biological subtypes based on anatomical location, age and clinical outcome, which now defines the need to tailor therapy even for histologically similar tumors. These findings now provide reasons for a paradigm shift in therapy, which should profile future clinical trials focused on targeted therapeutic strategies and risk-based treatment. The need to diagnose and differentiate the aggressive variants, which include the posterior fossa group A and the supratentorial RELA fusion subtypes, is imperative to escalate therapy and improve survival.

In 2017, an autologous chimeric antigen receptor (CAR) T cell therapy indicated for children and young adults with relapsed and/or refractory CD19+ acute lymphoblastic leukaemia became the first gene therapy to be approved in the USA. This innovative form of cellular immunotherapy has been associated with remarkable response rates but is also associated with unique and often severe toxicities, which can lead to rapid cardiorespiratory and/or neurological deterioration. Multidisciplinary medical vigilance and the requisite health-care infrastructure are imperative to ensuring optimal patient outcomes, especially as these therapies transition from research protocols to standard care. Herein, authors representing the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Hematopoietic Stem Cell Transplantation (HSCT) Subgroup and the MD Anderson Cancer Center CAR T Cell Therapy-Associated Toxicity (CARTOX) Program have collaborated to provide comprehensive consensus guidelines on the care of children receiving CAR T cell therapy., Chimeric antigen receptor (CAR) T cell therapies have impressive activity in the treatment of cancer but are associated with potentially fatal toxicities. In light of the approval of CAR T cell therapy for paediatric patients, a panel of experts from the Hematopoietic Stem Cell Transplantation (HSCT) Subgroup of the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network, the CAR T Cell Therapy-Associated Toxicity (CARTOX) Program at The University of Texas MD Anderson Cancer Center, and several other institutions have developed consensus guidelines for the use and management of these treatments in paediatric patients, which are presented herein.

Phacilitate held a Special Interest Group workshop event in Edinburgh, UK, in May 2017. The event brought together leading stakeholders in the cell therapy bioprocessing field to identify present and future challenges and propose potential solutions to automation in cell therapy bioprocessing. Here, we review and summarize discussions from the event. Deep biological understanding of a product, its mechanism of action and indication pathogenesis underpin many factors relating to bioprocessing and automation. To fully exploit the opportunities of bioprocess automation, therapeutics developers must closely consider whether an automation strategy is applicable, how to design an ‘automatable’ bioprocess and how to implement process modifications with minimal disruption. Major decisions around bioprocess automation strategy should involve all relevant stakeholders; communication between technical and business strategy decision-makers is of particular importance. Developers should leverage automation to implement in-process testing, in turn applicable to process optimization, quality assurance (QA)/ quality control (QC), batch failure control, adaptive manufacturing and regulatory demands, but a lack of precedent and technical opportunities can complicate such efforts. Sparse standardization across product characterization, hardware components and software platforms is perceived to complicate efforts to implement automation. The use of advanced algorithmic approaches such as machine learning may have application to bioprocess and supply chain optimization. Automation can substantially de-risk the wider supply chain, including tracking and traceability, cryopreservation and thawing and logistics. The regulatory implications of automation are currently unclear because few hardware options exist and novel solutions require case-by-case validation, but automation can present attractive regulatory incentives.

Simple Summary Pediatric patients with relapsed or refractory acute lymphoblastic leukemia (ALL) or lymphoma (LBL) currently have unsatisfactory outcomes, and novel treatment options are needed. Venetoclax is approved for adult patients with several types of leukemia and is being investigated in the pediatric population. Here, we retrospectively reviewed the safety and efficacy of venetoclax for the treatment of ALL/LBL in the pediatric and young adult populations. The purpose of this study is to provide evidence that venetoclax is safe and effective to use in pediatric patients with ALL/LBL and should be considered in both the relapsed and upfront settings. Abstract Venetoclax is approved for adult patients with chronic lymphocytic leukemia and acute myeloid leukemia. Expanding its use to the pediatric population is currently under investigation, but more robust data are needed. We retrospectively analyzed the safety and efficacy of venetoclax in children/AYA with ALL/LBL. We identified 18 patients (T-cell ALL, n = 7; T-cell LBL, n = 6; B-cell ALL, n = 5) aged 6–22 years. No new venetoclax safety signals were identified; the most common toxicity was myelosuppression. No deaths occurred within 30 days from the start of the therapy. A mean of 2.6 (range 0–8) prior lines of therapy were given. The mean duration of venetoclax was 4.06 months (range 0.2–24.67 months). Complete remission was achieved in 11 (61%) patients. Of the eight patients who remain alive, four are continuing on venetoclax combination therapy, and four proceeded to hematopoietic stem cell transplantation. Three patients who initially achieved CR, later relapsed, and are deceased. Nine patients are deceased, and one patient was lost to follow-up. Overall survival is 9.14 months (range 1.1–33.1), and progression-free survival is 7.34 months (range 0.2–33.1). This is the largest cohort of pediatric/AYA patients who received venetoclax for ALL/LBL. Our data support the consideration of venetoclax-based regimens in pediatric patients with R/R ALL/LBL and its investigation as upfront therapy for T-cell ALL/LBL.

Introduction Myelodysplastic syndrome (MDS) is mainly a disease of the elderly, with a median age of 72 years. There is little information regarding Adolescent and Young Adult (AYA) Patients with Myelodysplastic syndrome (MDS). AYA cancer patients are defined as those patients ages between 15-39 years according to NCCN guidelines. This retrospective study describes the general characteristics, cytogenetics, mutational profiles, treatments, and outcomes of AYA with MDS Diagnosis. Methodology We analyzed the clinical database of a single tertiary care center for patients with MDS ages between 18- 39 years from January 2012 through December 2020. We used 18 years as age cut-off, and not 15, due to the structure of our cancer center. Results In this retrospective study, 65 patients were identified. The median age was 30 (18-39) years, with female sex predominance (n=37) (57%). Baseline laboratory findings: median hemoglobin (HgB) was 9.45gm/dL (6.2-14.8), white blood cells (WBC) (3.4x10e9/L [0.3-136.9], platelets 63,000 (5,000-479,000), bone marrow blast 4% [0-17], IPSS was low in 11 patients (17%), intermediate- 1 in 23 (35%), intermediate- 2 16(25%) and high 8 (12%). 58 patients (89%) had MDS and seven (11%) had CMML. Twenty patients (30.7%) had a previous history of other cancers, with sarcomas being the most frequent with 6 cases (9.2%). Therapy-related MDS (t-MDS) was observed in 18 patients (27.6%). Ten patients (15.3%) had bone marrow failure syndrome, with GATA2 syndrome being the most frequent. Fanconi anemia and Schwachman-Diamond Syndrome was documented in two patients respectively. The most recurrent cytogenetics alterations were diploid in 20 patients (30.7%), followed by complex in 11 (16.9%). The most frequent mutations were RUNX1 (somatic)15%, followed by DNMT3A, TP53, NRAS, GATA2 and TET2, as shown in the Figure 1. Hypomethylating agents (HMAs) were the most frequent first line treatment used in 16 patients (24.6%). Forty-three patients (66%) underwent an allogeneic bone marrow transplant with a median OS (95% CI) of 27 months (9-45). While for the group of patients who didn't receive transplant, it was 21 months (7-69) (p=0.19) vs patients who didn't receive transplant. Allogeneic transplantation in TP53-mutated patients resulted in a Median OS (95% CI) of 21 months (12-65). Patients who progressed into AML had an inferior median OS (95% CI) of 21 months (12-65) for vs 28 months (11-47) for those who did not progressed to AML(p=0.025). In multivariate analysis expression of RUNX1 and NOTCH1, was associated with inferior outcomes (p-value=0.035, 0.004 respectively) (Figure 2,3 and 4) Conclusion In our cohort, MDS occurred as part of marrow failure syndrome or consequence of therapy t-MDS. Somatic RUNX1 was the most frequent mutation in AYA group with MDS. RUNX1, NOTCH1 and Tp53 mutated patients had worse outcome. Most patients underwent bone marrow transplant Figure 1 Figure 1. Disclosures Jabbour: Amgen, AbbVie, Spectrum, BMS, Takeda, Pfizer, Adaptive, Genentech: Research Funding. Daver: Abbvie: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Glycomimetics: Research Funding; Novimmune: Research Funding; Amgen: Consultancy, Research Funding; FATE Therapeutics: Research Funding; Hanmi: Research Funding; Sevier: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Trovagene: Consultancy, Research Funding; Trillium: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy, Other: Data Monitoring Committee member; Dava Oncology (Arog): Consultancy; Celgene: Consultancy; Syndax: Consultancy; Shattuck Labs: Consultancy; Agios: Consultancy; Kite Pharmaceuticals: Consultancy; SOBI: Consultancy; STAR Therapeutics: Consultancy; Karyopharm: Research Funding; Newave: Research Funding. Kadia: Liberum: Consultancy; Novartis: Consultancy; Pfizer: Consultancy, Other; Jazz: Consultancy; BMS: Other: Grant/research support; Amgen: Other: Grant/research support; Pulmotech: Other; Genentech: Consultancy, Other: Grant/research support; Aglos: Consultancy; Sanofi-Aventis: Consultancy; Genfleet: Other; Astellas: Other; Ascentage: Other; AstraZeneca: Other; AbbVie: Consultancy, Other: Grant/research support; Dalichi Sankyo: Consultancy; Cure: Speakers Bureau; Cellonkos: Other. Pemmaraju: LFB Biotechnologies: Consultancy; Incyte: Consultancy; Protagonist Therapeutics, Inc.: Consultancy; Abbvie Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; CareDx, Inc.: Consultancy; DAVA Oncology: Consultancy; Stemline Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Cellectis S.A. ADR: Other, Research Funding; Celgene Corporation: Consultancy; Novartis Pharmaceuticals: Consultancy, Other: Research Support, Research Funding; Roche Diagnostics: Consultancy; Daiichi Sankyo, Inc.: Other, Research Funding; Affymetrix: Consultancy, Research Funding; Plexxicon: Other, Research Funding; ASH Communications Committee: Membership on an entity's Board of Directors or advisory committees; Samus: Other, Research Funding; ASCO Leukemia Advisory Panel: Membership on an entity's Board of Directors or advisory committees; Aptitude Health: Consultancy; Springer Science + Business Media: Other; MustangBio: Consultancy, Other; Sager Strong Foundation: Other; HemOnc Times/Oncology Times: Membership on an entity's Board of Directors or advisory committees; Dan's House of Hope: Membership on an entity's Board of Directors or advisory committees; Clearview Healthcare Partners: Consultancy; Blueprint Medicines: Consultancy; Bristol-Myers Squibb Co.: Consultancy; ImmunoGen, Inc: Consultancy; Pacylex Pharmaceuticals: Consultancy. Kantarjian: NOVA Research: Honoraria; KAHR Medical Ltd: Honoraria; Precision Biosciences: Honoraria; BMS: Research Funding; Amgen: Honoraria, Research Funding; Jazz: Research Funding; Ascentage: Research Funding; Immunogen: Research Funding; Daiichi-Sankyo: Research Funding; Ipsen Pharmaceuticals: Honoraria; Astra Zeneca: Honoraria; Astellas Health: Honoraria; Aptitude Health: Honoraria; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Taiho Pharmaceutical Canada: Honoraria.

Background : Although in recent clinical trials the 5-year event-free survival rates for pediatric Acute Myeloid Leukemia (AML) range between 49% and 64%, relapse still occurs in up to one-third of cases. Long-term outcomes of children with relapsed or refractory disease remain poor, with overall survival under 40%. Novel drugs directed toward distinct pathways and new molecular targets are required to continue improving outcomes for this aggressive hematological disease. Use of the BCL-2 inhibitor, venetoclax, has improved overall and event-free survival in adult patients with newly diagnosed, intensive-chemotherapy ineligible AML, however, its effects in pediatric AML patients remain unclear. We reviewed our multi-institutional experience with venetoclax in this population. Methods : We performed a retrospective review of patients ages 0 to 23 y/o with AML and treated with at least one cycle of venetoclax at either MD Anderson Cancer Center or Texas Children's Hospital prior to May 2021. Flow cytometry was used to assess morphology and response to therapy. Adverse events (AEs) associated with venetoclax were graded according to the Common Terminology Criteria for Adverse Events version 5.0. Descriptive statistics were used to report efficacy and toxicity data. Results : 46 patients with AML who received venetoclax-containing regimens were identified. There was a similar proportion of males and females (52% and 48%) and most were Caucasian (48%). The median age was 21 years (range, 1-23) with eight patients (17%) Conclusion : Our findings suggest that in pediatric and early young adults, venetoclax is well-tolerated with a variety of cytotoxic agents and has a safety profile similar to that in adults. Patients should be monitored closely for prolonged myelosuppression and febrile neutropenia. As dosing varied significantly in our cohort, more studies are needed to establish an optimal dose in the pediatric population. Longer follow-up is expected to provide more insight on the improvement venetoclax may have on overall and progression-free survival. Figure 1 Figure 1. Disclosures Kadia: Sanofi-Aventis: Consultancy; Dalichi Sankyo: Consultancy; Genentech: Consultancy, Other: Grant/research support; Genfleet: Other; AstraZeneca: Other; Astellas: Other; Pulmotech: Other; Cure: Speakers Bureau; Cellonkos: Other; Jazz: Consultancy; Pfizer: Consultancy, Other; Ascentage: Other; Novartis: Consultancy; Liberum: Consultancy; BMS: Other: Grant/research support; Amgen: Other: Grant/research support; Aglos: Consultancy; AbbVie: Consultancy, Other: Grant/research support. Konopleva: Cellectis: Other: grant support; F. Hoffmann-La Roche: Consultancy, Honoraria, Other: grant support; KisoJi: Research Funding; Calithera: Other: grant support, Research Funding; Rafael Pharmaceuticals: Other: grant support, Research Funding; Ascentage: Other: grant support, Research Funding; Sanofi: Other: grant support, Research Funding; Forty Seven: Other: grant support, Research Funding; Ablynx: Other: grant support, Research Funding; Agios: Other: grant support, Research Funding; AstraZeneca: Other: grant support, Research Funding; Novartis: Other: research funding pending, Patents & Royalties: intellectual property rights; Reata Pharmaceuticals: Current holder of stock options in a privately-held company, Patents & Royalties: intellectual property rights; Stemline Therapeutics: Research Funding; Genentech: Consultancy, Honoraria, Other: grant support, Research Funding; Eli Lilly: Patents & Royalties: intellectual property rights, Research Funding; AbbVie: Consultancy, Honoraria, Other: Grant Support, Research Funding. DiNardo: Takeda: Honoraria; Notable Labs: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; ImmuneOnc: Honoraria, Research Funding; AbbVie: Consultancy, Research Funding; Forma: Honoraria, Research Funding; Agios/Servier: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria; Foghorn: Honoraria, Research Funding; Celgene, a Bristol Myers Squibb company: Honoraria, Research Funding. Daver: Bristol Myers Squibb: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Sevier: Consultancy, Research Funding; Novartis: Consultancy; Astellas: Consultancy, Research Funding; Glycomimetics: Research Funding; Novimmune: Research Funding; Hanmi: Research Funding; Genentech: Consultancy, Research Funding; Trillium: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; FATE Therapeutics: Research Funding; ImmunoGen: Consultancy, Research Funding; Abbvie: Consultancy, Research Funding; Trovagene: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Other: Data Monitoring Committee member; Dava Oncology (Arog): Consultancy; Celgene: Consultancy; Syndax: Consultancy; Shattuck Labs: Consultancy; Agios: Consultancy; Kite Pharmaceuticals: Consultancy; SOBI: Consultancy; STAR Therapeutics: Consultancy; Karyopharm: Research Funding; Newave: Research Funding. Short: AstraZeneca: Consultancy; Jazz Pharmaceuticals: Consultancy; NGMBio: Consultancy; Novartis: Honoraria; Astellas: Research Funding; Takeda Oncology: Consultancy, Research Funding; Amgen: Consultancy, Honoraria. Issa: Kura Oncology: Consultancy, Research Funding; Syndax Pharmaceuticals: Research Funding; Novartis: Consultancy, Research Funding. Ravandi: Amgen: Honoraria, Research Funding; Xencor: Honoraria, Research Funding; Taiho: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Novartis: Honoraria; AstraZeneca: Honoraria; AbbVie: Honoraria, Research Funding; Prelude: Research Funding; Astex: Honoraria, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Syros Pharmaceuticals: Consultancy, Honoraria, Research Funding. Kantarjian: Ascentage: Research Funding; Astra Zeneca: Honoraria; Pfizer: Honoraria, Research Funding; Daiichi-Sankyo: Research Funding; KAHR Medical Ltd: Honoraria; Ipsen Pharmaceuticals: Honoraria; NOVA Research: Honoraria; Novartis: Honoraria, Research Funding; Immunogen: Research Funding; Astellas Health: Honoraria; BMS: Research Funding; Aptitude Health: Honoraria; Jazz: Research Funding; AbbVie: Honoraria, Research Funding; Precision Biosciences: Honoraria; Amgen: Honoraria, Research Funding; Taiho Pharmaceutical Canada: Honoraria.

Background: Acute myeloid leukemia (AML) is rare but accounts for 20% of leukemia in the pediatric, adolescent and young adult (AYA) population. Five-year survival ranges widely from 22-90% based on subtype and cytogenetic abnormalities. The risk stratification of AML continues to evolve with increased recognition of inferior prognostic factors in the adult population; however, there has been a lack of similar progress in pediatrics. The DNA methyltransferase 3A (DNMT3A) mutation, most frequently at arginine 882 (DNMT3A mut) is observed in 14-34% of adult AML patients and is associated with inferior outcomes. This mutation shows evidence of anthracycline resistance, which may contribute to its poor prognosis as standard induction therapy for AML consists of a backbone of anthracyclines and purine analogs. Overall survival (OS) and disease-free survival (DFS) are improved in adult patients with DNMT3A mutation who receive consolidative allogeneic hematopoietic stem cell transplant (allo-HSCT). DNMT3A mutation has also been reported in the pediatric and AYA AML in 0-1.5% of cases with unclear prognostic implications. In case its presence in this patient population confers inferior outcomes similar to those seen in adults, these patients may also benefit from allo-HSCT Objective: Describe the outcome of pediatric and AYA AML patients with DNMT3A mutations Methods: This study was approved by the institutional review board at the University of Texas at MD Anderson Cancer Center. All patients aged ≤25 years, diagnosed with AML who underwent treatment at our institution between May 1st, 2014 and November 30 th 2020 were screened. Patients who did not undergo testing for DNMT3A mutation were excluded. Outcomes for patients with and without the DNMT3A mutation who underwent allo-HSCT were compared. Results: One hundred and five patients were diagnosed with AML during the study period. Forty-five patients were not tested for the DNMT3A mutation and were excluded. Sixty patients were tested for the DNMT3A mutation and were included in the analysis. Seven patients (11.7%) (4 males, 3 females) were found to be DNMT3A mutation positive (+ve). Four of them had the R882 missense mutation. Thirty-three patients (33/60; 55%) (16 males, 17 females) underwent allo-HSCT, with 6 of those being DNMT3A+ve. The median age of DNMT3A+ve and DNMT3A negative(-ve) patients undergoing allo-HSCT was 18.5 years (12.6-22.7) and 20 years (11.1-24) respectively (Figure1). Five patients who were DNMT3A+ve underwent allo-HSCT due to disease relapse and 1 patient due to associated FLT3 mutation. Median overall survival was similar in patients with and without DNMT3A mutations who received allo-HSCT at 744 (515-2473) days and 729(48-2492) days respectively (p value =0.77) (Figure 1). Median OS was significantly lower in the one DNMT3A +ve patient who did not undergo allo-HSCT at 430 days compared to those who underwent allo-HSCT (p value=0.01). Two of the six (33.3%) DNMT3A +ve patients who underwent allo HSCT died due to disease relapse (DR). The one DNMT3A patient who did not undergo allo HSCT died due to refractory disease. In the 27 patients who were DNMT3A -ve and received allo-HSCT, 13 died (13/27;48.1%), 6 from disease relapse (6/27; 22.2%), 2 due to multiorgan failure (2/27; 7.4%) and 5 unknown (5/27;18.5%). Relapse-free survival (RFS) was not significantly different between DNMT3A+ve and DNMT3A -ve patients who underwent allo-HSCT at 422 (31-1948) days and 271 (65-2048) days respectively (p value = 0.7).Of the four patients with the R882 missense mutation, 2 died due to DR (one patient at 192 days post allo-HSCT, one patient who did not undergo allo-HSCT at 352 days after achieving clinical remission one(CR1). Of the 3 patients with non R882 mutations, one died due to DR at 98 days post allo-HSCT. Conclusion: DNMT3A mutations, although rare in AML, may be associated with poor prognosis and impact risk stratification. This study suggest that consolidative allogeneic HSCT is a reasonable management consideration for this subgroup of patients. DNMT3A is not included in the current AML risk stratification of pediatric and young adult patients and further research is needed to determine the clinical significance of DNMT3A mutations in pediatric and AYA patients with AML and the impact of upfront allo-HSCT. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Hematopoietic cell transplantation (HCT) and cellular therapy (CT) are potentially lifesaving treatments for children with malignant and nonmalignant diseases. Advancements in care have led to expanding patient eligibility, with overall reduced morbidity and improved survival. Survival for HCT patients requiring pediatric intensive care unit (PICU) admission have improved. While almost half of pediatric patients receiving CAR-T therapy may require intensive care support, overall survival remains promising. However, patients undergoing HCT remain at risk for debilitating and life-threatening complications such as sinusoidal obstructive syndrome (S0S), infection, and graft-versus-host disease (GVHD); patients receiving chimeric antigen receptor (CAR) and other T-cell therapies are at risk for unique toxicities such as cytokine release syndrome (CRS) and CAR-T-related encephalopathy syndrome (CRES). Judicious patient and treatment selection, vigilant monitoring, and prompt interventions may reduce the need for PICU admission among HCT and CAR-T recipients. When PICU intervention is required, early intervention, excellent interdisciplinary communication, prognostication, and intensive support may improve outcomes.

We report on the development of a highly sensitive and novel surface enhanced Raman scattering (SERS) substrate for the detection of analytes, such as rhodamine 6G (R6G), glyphosate, melamine and salicylic acid. The fabrication steps include (a) cleaning the surface of the Cu-grids on carbon support layer with an initial glow discharge treatment, (b) layering of carbon film with a thickness of 3 nm, (c) application of 24 μl volumes of silver colloid to form silver dendrites, and (d) a glow discharge treatment of silver dendrites to remove surface debris or particles. The substrate demonstrated excellent SERS measurement reproducibility, along with a significant SERS enhancement factor of 6.1 × 105 of Raman signals and highly informative chemical signature of R6G. The SERS substrate can be used as a quantitative tool. The protocols for fabrication of the substrate are inexpensive and it is more sensitive than conventional Raman technique and a commercial product. Highly sensitive detection limits for R6G (240 ppb), glyphosate (845 ppb), melamine (630 ppb) and salicylic acid (600 ppb) were achieved with this substrate. This study has shown that the Ag-Cu-grid substrate is well suited for routine environmental monitoring of chemical residues and the detection of plant metabolites. The stability of the nano-structured Ag-Cu-grid was demonstrated during a 4 week storage period.

DNA mismatch repair machinery is an integral part of the human genome and its defect has been involved in tumorigenesis and treatment resistance. Heterozygous monoallelic germline loss of function in MLH-1, MSH-2, MSH-6 or PMS-2 is involved in Lynch syndrome, whereas biallelic mutations cause constitutional mismatch repair deficiency (CMMRD) which is associated with hematologic malignancies and glioblastoma. We report here the clinical characterization and molecular analyses of 7 patients who presented with gliomas and MMR machinery aberrations. Two patients had a clinical diagnosis of NF-1 with dermatologic stigmata, of whom one patient has CMMRD and the other has Lynch syndrome. Two patients had a known family history of Lynch syndrome upon their diagnosis of glioma. Three patients with high-grade glioma and negative family history, 2 had germline mutations in MMR genes, and one had numerous mutations including MMR genes with microsatellite instability. Patients were initially treated with chemotherapy and radiation for high-grade gliomas (HGG); 5/7 had progression. Median time to progression was 12 months (range: 5–52), and median time from progression to death was 7 months (range: 2–25). One patient had low-grade glioma initially but progressed to HGG and is currently on therapy. Another patient treated with temozolomide and radiation is currently receiving maintenance therapy without any disease recurrence. Although the literature data on brain tumors with MMR deficiency is limited, these consistently show that MMRD-associated gliomas are treatment-resistant and have a dismal outcome. Collaborative efforts are needed to better understand this subgroup of pediatric HGG and to define optimal treatment strategy.

Background : Ten to fourteen percent of Ewing sarcoma (ES) study participants treated nationwide with IGF-1 receptor (IGF-1R)-targeted antibodies achieved tumor regression. Despite this success, low response rates and short response durations (approximately 7-weeks) have slowed the development of this therapy. Methods: We performed a meta-analysis of five phase-1b/2 ES-oriented trials that evaluated the anticancer activity of IGF-1R antibodies +/&minus, mTOR inhibitors (mTORi). Our meta-analysis provided a head-to-head comparison of the clinical benefits of IGF-1R antibodies vs. the IGF-1R/mTOR-targeted combination. Available pretreatment clinical samples were semi-quantitatively scored using immunohistochemistry to detect proteins in the IGF-1R/PI3K/AKT/mTOR pathway linked to clinical response. Early PET/CT imaging, obtained within the first 2 weeks (median 10 days), were examined to determine if reduced FDG avidity was predictive of progression-free survival (PFS). Results: Among 56 ES patients treated at MD Anderson Cancer Center (MDACC) with IGF-1R antibodies, our analysis revealed a significant ~two-fold improvement in PFS that favored a combination of IGF-1R/mTORi therapy (1.6 vs. 3.3-months, p = 0.042). Low pIGF-1R in the pretreatment specimens was associated with treatment response. Reduced total-lesion glycolysis more accurately predicted the IGF-1R response than other previously reported radiological biomarkers. Conclusion: Synergistic drug combinations, and newly identified proteomic or radiological biomarkers of IGF-1R response, may be incorporated into future IGF-1R-related trials to improve the response rate in ES patients.

Introduction: Patients with absolute neutrophil count (ANC) Methods: We performed a five-year IRB-approved, retrospective chart review of patients referred to a Pediatric Hematology-Oncology clinic for isolated neutropenia. Patients were excluded if they also had anemia or thrombocytopenia at the time of the referral. Degree of neutropenia was categorized: 1) at the time of referral, 2) at the lowest value, and 3) at the current ANC as Mild: 1.001-1.500 x109/L, Moderate: 0.501-1.000 x109/L, Severe: 0.201-0.5 x109/L, or Very Severe ≤0.2 x109/L. Descriptive statistics and odds ratios were performed. Results: Among 154 patients referred with isolated neutropenia over five years, 45 (29%) had mild neutropenia, 65 (42%) had moderate neutropenia, 29 (19%) had severe neutropenia, and 15 (10%) had very severe neutropenia. Only 29 (19%) patients progressed to a lower ANC category than their referral ANC category. At a median follow-up of 12 months, 101 (66%) patients had resolved neutropenia, 40 (26%) patients had mild, ten (6%) patients had moderate, three patients had severe, and one patient had very severe neutropenia. Most patients (54%) were not identified with a specific diagnosis. The most common diagnoses included viral suppression (16%), autoimmune neutropenia (14%) and drug induced neutropenia (8%). The most common medications reported as responsible for neutropenia were either anti-epileptic medications or immunosuppressant medications. No patients were diagnosed with a malignancy. Black patients had a 3.5 times higher odds of having persistent, mild, undiagnosed neutropenia which, for some patients, may be benign ethnic neutropenia. Seven (4.5%) patients received G-CSF therapy. Five patients were either managed by a Rheumatologist or an Immunologist. Finally, there were 16 hospitalizations that occurred in 10 patients for a prevalence of one admission for every 21 patient years. The most common admission diagnosis was febrile neutropenia without subsequent bacteremia (n=13). Conclusion: Most pediatric patients referred for isolated neutropenia do not progress, develop leukemia, or require sub-specialty interventions. Hospitalization of patients referred for isolated neutropenia is rare as is bacteremia. This study provides important outcome data that can improve our counseling of pediatric patients identified with isolated neutropenia. Disclosures Howard: Novartis: Consultancy. Lebensburger:Novartis: Consultancy; Pfizer: Research Funding.

INTRODUCTION The new understanding of molecular pathways in cancer is paving the way towards personalized cancer medicine, especially in refractory disease. High-grade gliomas (HGG) are common pediatric brain tumors that tend to recur, with no available standard therapy upon recurrence. HGG are challenging tumors with illusive biology and poor outcome. We report here the molecular testing of 27 pediatric HGG patients. MATERIALS AND METHODS An analysis of pediatric patients with HGG treated at UT MD Anderson Cancer Center (MDACC) who underwent molecular genetic profiling using next generation sequencing with different genomic panels (AmpliSeq™Cancer Hotspot and Oncomine Panels – by Thermo Fisher Scientific). RESULTS 27 patients with HGG (median age 14 years, range 3–18 years old) underwent genomic profiling. Primary diagnoses were glioblastoma multiforme (n=22), anaplastic astrocytoma (n = 2), gliosarcoma (n= 1), anaplastic pleomorphic xanthoastrocytoma (n= 1) and anaplastic oligoastrocytoma (n= 1). There are 46 genes common to the panels used. The most common mutation was in TP53 (73%). Other mutations included PIK3CA (19%), IDH1 (11.5%), 7.7% for ATM, EGFR and PTEN, and 3.8% for BRAF, FGFR1 and FGFR2. 24 out of 27 patients were tested at initial diagnosis and 3 upon relapse/progression. Patients at initial diagnosis received standard of care therapy of radiation and temozolomide. Only 5 patients received targeted therapy upon progression/recurrence. Some challenges of genomically-matched therapy included lack of clinical trials accepting pediatric patients, unavailability of a liquid form of a drug, and insurance disapproval for off-label use. CONCLUSION The next generation of therapy for childhood cancers will be based upon in-depth molecular phenotyping that may facilitate the development of rational risk-adapted and target-based therapies. This cohort, though limited by sample size, highlights the opportunity to perform molecular testing and identification of alterations in actionable genes.

The past few decades have seen marked improvements in survival rates of osteosarcoma due to the advent of modern chemotherapy, radiotherapy, and surgical techniques. However, for patients presenting with metastatic disease, five-year survival rates have remained dismal, hovering around 20%. Repeated failures of clinical trials to confirm potential therapeutic options highlight the need for more accurate pre-clinical testing. Currently, the field of cancer research relies heavily on monolayer culture methods on hard plastic or glass in vitro models; there is a dearth of pre-clinical models that accurately recapitulate the tumor-microenvironment interactions. Matrix stiffness has been implicated in modulating intracellular signaling pathways that promote cancer cell survival, proliferation, and stem cell fate. We have developed a novel three-dimensional (3D) tumor model with variable mechanical properties in order to determine the effect of substrate stiffness and tissue architecture on osteosarcoma cell phenotype, plasticity, and response to therapy. We employed coaxial electrospinning techniques to fabricate highly porous fibrous mesh scaffolds that mimic the bone microenvironment. By controlling the ratio of poly(ϵ-caprolactone) (PCL) and gelatin (PCL:gelatin, core:shell, respectively) in constituent fibers, we were able to manipulate the range of tensile moduli of individual fibers over three orders of magnitude, from 68.91 ± 8.77 kPa to 66.05 ± 7.61 MPa. Osteosarcoma cells cultured in these variable mechanical environments responded by modulating the localization and expression of Hippo pathway regulators. YAP downregulation correlated with decreasing fiber stiffness while both YAP and TAZ had decreasing nuclear:cytoplasmic ratio in less stiff environments. Furthermore, the IGF-1/mTOR axis was downregulated in 3D conditions compared to monolayers and a strong upregulation of Sox2, a stem cell transcription factor, was observed in all 3D conditions. Correspondingly, in the presence of agents targeting the IGF-1/mTOR axis, dose response curves to doxorubicin indicated that IC50 values increase with decreasing substrate stiffness. These phenotypic changes indicate that osteosarcoma cells respond to both stiffness and architecture by modulating the Hippo and IGF-1R/mTOR pathways and increasing cancer stem cell qualities and chemoresistance. We sought to validate our model using osteosarcoma patient biopsies. Analysis of tumor samples from 36 osteosarcoma patients confirmed that YAP/TAZ localization and nuclear pIGF-1R/IGF-1R in our 3D models recapitulated phenotypes observed in patient samples. Our models highlight the need for incorporation of mechanical and architectural cues in the preclinical study of cancer biology as these signals have drastic impacts on osteosarcoma phenotypes and responses to therapy. Citation Format: Eric R. Molina, Letitia K. Chim, Maria C. Salazar, Shail M. Mehta, Brian A. Menegaz, Salah-Eddine Cherradi-Lamhamedi, Tejus Satish, David McCall, Sana Mohiuddin, Ana Maria Zaska, Katherine Jane Grande-Allen, Joseph A. Ludwig, Antonios G. Mikos. Mechanically tunable 3D microenvironments modulate tumor cell phenotype: Models of mechanotransduction and drug resistance in osteosarcoma [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 LB-028.

This article reviews current thinking and literature about the concept of sexual behavior and those in the clergy profession. A bibliographic reference section is provided.

Energy dispersive X-ray microanalysis (XRMA) in a scanning electron microscope (SEM) was used as a method to measure elemental silicon (Si) and phosphorus (P) in dinoflagellate cysts. Cysts were prepared by quick deep freezing and then freeze-drying, thereby avoiding the addition of preservatives. Cysts of Ceratium hirundinella collected from Lake Erken, Sweden and Esthwaite Water, UK, and Ceratium furcoides collected from Esthwaite Water, were analysed and compared. The hypothesis that cysts are able to assimilate P during dormancy was tested in the laboratory by incubating newly collected cysts of C. hirundinella in medium with and without phosphate. The analyses showed that there was no difference in P content between C. hirundinella and C. furcoides, suggesting that P content reflects differences in physiological status rather than species. C. hirundinella had a significantly higher Si content than C. furcoides, which agrees with earlier studies. Comparison of cysts of C. hirundinella from different y...

Dried, milled perennial ryegrass samples were processed using chemical and physical treatments and the extracted cellulose products were analysed for yield, crystallinity by X-ray Diffraction (XRD) and for purity using Thermogravimetric Analysis (TGA), Pyrolysis–Gas Chromatography/Mass Spectrometry (Py-GC/MS) and Fourier Transform Infrared (FTIR) spectroscopy. Extraction protocols examined the use of chemical chelation, acid and alkaline hydrolysis, along with physical degradation methods. Highest product yields were obtained using single step chemical protocols followed by physical processing, however, these products had low crystallinity and higher amorphous fraction content. Multistep chemical processing to completely remove hemicellulose and lignin with an alkali refluxing step, delivered lower yielding cellulose products of greater crystallinity and purity. In combination, the four instrumental techniques highlighted removal of amorphous fractions, providing rapid, accurate compositional data on the extracted cellulose products.

The present study was carried out to evaluate the effects of biologically active atriopeptin II (APII) in synchronously contracting monolayer cultures of rat ventricular myocytes. The effects of 10 nM APII on Ca influx, contractile behavior and cyclic nucleotide content of the cells were measured. Applied acutely APII had no effect on Ca influx. There was however a time-dependent effect such that after 30 min Ca influx (pmol/cm2/s) had declined from a control (mean +/- S.E.M.) of 1.53 +/- 0.16 to 1.02 +/- 0.07 (P less than 0.001; n = 6). There was parallel decline in both the magnitude and velocity of cell edge motion which was maximal in 30 min at which time cell edge motion measured 65.3 +/- 4.4% of control. Treatment with APII for 30 min decreased cAMP (pmol/mg protein) from 5.35 +/- 0.17 to 2.86 +/- 0.24 (P less than 0.001; n = 5). At the same time cGMP (pmol/mg protein) increased from 0.86 +/- 0.21 to 2.14 +/- 0.33 (P less than 0.001; n = 5). Further studies elucidated the fact that the decline in Ca influx and contractile behavior was dependent on the decrease in cAMP rather than the increase in cGMP. Pre-treatment of the cells with 5 ng/ml of pertussis toxin to ADP-ribosylate the Gi protein abolished the effects of APII on cAMP, Ca influx and contractile behavior. The results indicate that in myocardial cells, as in other cells, APII stimulates guanylate cyclase and inhibits adenylate cyclase. The resultant fall in cAMP decreases Ca influx and negatively influences the contractile behavior of the cells.

Europski tekstilci udruženi u European Technology Platform for the Future of Textile donijeli su devet smjernica za razvoj tekstilstva u Europi. Nova primjena tekstilne tehnologije za izradu materijala visokih svojstava (medicinski tekstil, tekstil za zaštitu i sport) jedna je od njih. U skladu s tim, ovaj rad je pokušaj modifikacije površine poliesterske tkanine nanočesticama tribomehanički aktiviranog zeolita (TMAZ) radi postizanja veće UV zaštite. Sposobnost zaštite poliesterskom tkaninom namijenjenom uglavnom za ljetnu odjeću od nepovoljna UV zračenja ispitana je nakon površinskih modifikacija – alkalne hidrolize i obrade nanočesticama TMAZ-a te optičkog bijeljenja. Poliesterska tkanina od poli(etilen-tereftalata) površinski je modificirana alkalnom hidrolizom u natrijevoj lužini uz dodatak ubrzivača. Nanočestice TMAZ-a i optičko bjelilo Uvitex ERN-P (Ciba) naneseni su na površinu poliesterske tkanine termosol-postupkom. Površina tkanine istražena je skenirajućom elektronskom mikroskopijom (SEM). Određen je zaštitni učinak na UV zračenje te utjecaj na bjelinu (e. CIE whiteness, WCIE) i požućenje (e. Yellowing Index, YI) tkanine. Učinak površinskih modifikacija uspoređen je s učinkom UV apsorbera Tinofast PES (Ciba), posebno namijenjenoga za UV zaštitu. Postojanost obrade ispitana je nakon pranja. Alkalnom hidrolizom poliesterske tkanine dolazi do površinske modifikacije poliesterskog vlakna te tkanina poprima estetski izgled nalik na svilu. Obradom nanočesticama TMAZ-a ispunjavaju se napukline na alkalno hidroliziranoj poliesterskoj tkanini, dajući joj bolju adsorptivnost, dok estetski izgled ostaje. Optičkim bijeljenjem povećava se bjelina i UV zaštita. Optičko bjelilo i nanočestice TMAZ-a pokazuju sinergijski učinak na povećanje bjeline i UV zaštite. Primjenom nanočestica TMAZ-a na modificiranoj tkanini postignuta je podjednaka UV zaštita kao primjenom UV apsorbera, koja se neznatno smanjuje u pranju., Textile Scientists, united in the European Technology Platform for the Future of Textiles, established nine topics as guidance for future textile development. New textile application for achieving the materials for human performance (medical, protective and sports) is one of them. This paper is an attempt to modify the surface of polyester fabric with nanoparticles of tribomechanically activated zeolite (TMAZ) for achieving better UV protection. Polyester fabric protective ability from UV radiation (UV-R) was investigated after different treatments - alkaline hydrolysis, TMAZ nanoparticle treatment, and optical brightening. Polyester fabrics of poly(ethylene-terphtalate) was alkaline hydrolyzed in sodium hydroxide with addition of accelerator for achieving silk-like fabric for summer clothing purposes. TMAZ nanoparticles and optical brightener Uvitex ERN-P (Ciba) were applied on polyester fabric surface by thermosol process. Fabric surface was investigated by SEM. UV protection with modified fabric; fabric whiteness (CIE whiteness, CIEWH) and yellowness (Yellow Index, YI) were determined. The effect of surface modification was compared with the effect of UV absorber, Tinofast PES (Ciba) commercial product specially produced for UV protection. For the durability of treatment the fabrics were washed. Alkali hydrolysis modifies the surface of polyester fabric resulting in silk-like fabric. The treatment with TMAZ nanoparticles fills out the pits on fabric surface resulting in better adsorption, and retaining the silk-like appearance. Optical brightening increases the fabric whiteness and UV protection. Optical brightener and TAMZ nanoparticles show synergism in whiteness and UV protection increment. Modification with TMAZ nanoparticles results in UV protection similar to the one using UV absorber, which slightly goes off in the washing process.

Thrombocytopenia is a common reason for referral to a Pediatric Hematologist Oncologist. However, the need for acute intervention in patients with mild or moderate thrombocytopenia is likely a rare event. Because mild and moderate thrombocytopenia is less likely to need intervention and could resolve, the potentially stressful impact of referral to an Oncology center needs consideration. But with minimal literature to support the hypothesis that mild to moderate thrombocytopenia is unlikely associated with severe or progressive hematologic diseases, our ability to provide evidence based recommendations for need for referral is limited. To better understand the course for patients with mild and moderate thrombocytopenia, we conducted a retrospective chart review to assess the prevalence, outcomes, and need for intervention among patients referred for thrombocytopenia. Methods: We conducted a retrospective chart review of 1,140 patients referred to a large Pediatric Hematology Oncology program over a three year period (2012-2014). The diagnosis and demographics were recorded for every patient. Platelet counts at time of referral, lowest platelet count, and current platelet count were recorded and categorized as mild (plt: 100-149x103/mL), moderate (plt: 50-99 x103/mL), severe (plt: 20-49 x103/mL), and very severe (plt: Results: In a three year period (2012-2014), 1140 patients were referred to Pediatric Hematology Oncology, 902 of these patients for hematologic diagnoses. One hundred and three (11.4%) of 902 Hematology patients were referred for thrombocytopenia. The mean age of patients with thrombocytopenia was 9.2 years (s.d. 5.8yrs) and 58% were male. At the time of referral, 29% were categorized as mild, 33% were moderate, 17% severe and 21% very severe. The mean platelet count was 68 x103/mL (range 3-143). Younger patients had lower platelet counts (p Conclusion: Mild and moderate thrombocytopenia does not often progress or require interventions. Pediatricians should evaluate for Rheumatologic disorders in their initial work-up for mild to moderate thrombocytopenia as well as consider medication-induced thrombocytopenia. A safe and cost-effective approach to a patient with mild to moderate thrombocytopenia could be to observe repeat laboratory data (including ANA) in lieu of any other co-morbid condition. This approach could save families time, money, effort, and emotional stress in making appointments at large referral institutions. Disclosures No relevant conflicts of interest to declare.

Background Indoleamine 2,3-dioxygenase (IDO) is an enzyme with immune-suppressive properties that is commonly exploited by tumors to evade immune destruction. Anti-tumor T cell responses can be initiated in solid tumors, but are immediately suppressed by compensatory upregulation of immunological checkpoints, including IDO. In addition to these known effects on the adaptive immune system, we previously showed widespread, T cell-dependent complement deposition during allogeneic fetal rejection upon maternal treatment with IDO-blockade. We hypothesized that IDO protects glioblastoma from the full effects of chemo-radiation therapy by preventing vascular activation and complement-dependent tumor destruction. Methods To test this hypothesis, we utilized a syngeneic orthotopic glioblastoma model in which GL261 glioblastoma tumor cells were stereotactically implanted into the right frontal lobes of syngeneic mice. These mice were treated with IDO-blocking drugs in combination with chemotherapy and radiation therapy. Results Pharmacologic inhibition of IDO synergized with chemo-radiation therapy to prolong survival in mice bearing intracranial glioblastoma tumors. We now show that pharmacologic or genetic inhibition of IDO allowed chemo-radiation to trigger widespread complement deposition at sites of tumor growth. Chemotherapy treatment alone resulted in collections of perivascular leukocytes within tumors, but no complement deposition. Adding IDO-blockade led to upregulation of VCAM-1 on vascular endothelium within the tumor microenvironment, and further adding radiation in the presence of IDO-blockade led to widespread deposition of complement. Mice genetically deficient in complement component C3 lost all of the synergistic effects of IDO-blockade on chemo-radiation-induced survival. Conclusions Together these findings identify a novel mechanistic link between IDO and complement, and implicate complement as a major downstream effector mechanism for the beneficial effect of IDO-blockade after chemo-radiation therapy. We speculate that this represents a fundamental pathway by which the tumor regulates intratumoral vascular activation and protects itself from immune-mediated tumor destruction.