Jude Children's Research Research Articles

It's the Wrong Virus: Rapid Adaptation of Operations Inside a Highly Pathogenic Avian Influenza Select Agent Laboratory in Response to the 2019 SARS-CoV-2 Pandemic.

The Animal Biosafety Level 3 Enhanced (ABSL-3+) laboratory at St. Jude Children's Research Hospital has a long history of influenza pandemic preparedness. The emergence of SARS-CoV-2 and subsequent expansion into a pandemic has put new and unanticipated demands on laboratory operations since April 2020. Administrative changes, investigative methods requiring increased demand for inactivation and validation of sample removal, and the adoption of a new animal model into the space required all arms of our Biorisk Management System (BMS) to respond with speed and innovation. In this report, we describe the outcomes of three major operational changes that were implemented to adapt the ABSL-3+ select agent space into a multipathogen laboratory. First were administrative controls that were revised and developed with new Institutional Biosafety Committee protocols, laboratory space segregation, training of staff, and occupational health changes for potential exposure to SARS-CoV-2 inside the laboratory. Second were extensive inactivation and validation experiments performed for both highly pathogenic avian influenza and SARS-CoV-2 to meet the demands for sample removal to a lower biosafety level. Third was the establishment of a new caging system to house Syrian Golden hamsters for SARS-CoV-2 risk assessment modeling. The demands placed on biocontainment laboratories for response to SARS-CoV-2 has highlighted the importance of a robust BMS. In a relatively short time, the ABSL-3+ was able to adapt from a single select agent space to a multipathogen laboratory and expand our pandemic response capacity.

WHO and St Jude Children's Research Hospital announce childhood cancer medicines initiative.

On December 13, 2021, WHO and St Jude Children's Research Hospital jointly announced the launch of a new initiative to increase the supply of paediatric cancer medicines to low-income and middle-income countries (LMICs). The Global Platform for Access to Childhood Cancer Medicines will receive US$200 million in funding from St Jude Children's Research Hospital over the next 6 years. The platform aims to provide safe and effective cancer medication to approximately 120 000 children worldwide in 2022–27, with the expectation of a subsequent scale-up.

Impact of High Disease Burden on Survival in Pediatric Patients with B-ALL Treated with Tisagenlecleucel

CD19-specific chimeric antigen receptor (CAR) T-cell therapies, including the FDA-approved tisagenlecleucel, induce high rates of remission in pediatric patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, post-treatment relapse remains an issue. Optimal management of B-ALL after tisagenlecleucel treatment remains elusive, and continued tracking of outcomes is necessary to establish a standard of care for this population. We sought to evaluate outcomes on the real-world use of tisagenlecleucel in a contemporary pediatric patient population and to identify risk factors influencing event-free survival (EFS) and overall survival (OS). Additionally, we aimed to describe post-tisagenlecleucel management strategies, including use of allogeneic hematopoietic cell transplantation (AlloHCT) or repeat CAR T-cell infusions. We report on 31 pediatric and adolescent and young adult patients (AYA) with B-ALL, treated with lymphodepleting chemotherapy followed by tisagenlecleucel. Patients were treated at Johns Hopkins Hospital and St. Jude Children's Research Hospital between March 2018 and November 2020. Data on patient, disease, and treatment characteristics were collected retrospectively from medical records and described. EFS and OS were estimated by the Kaplan-Meier method and compared by the log-rank test. Single-factor and multiple-factor analysis of EFS and OS were performed by fitting Cox regression models. Of the 30 evaluable patients, 25 (83.3%) experienced a complete response, with 21 having negative minimal residual disease. Treatment was well tolerated, with expected rates of cytokine release syndrome (61.3%) and immune effector cell-associated neurotoxicity (29%). After initial complete response, 12 patients (48%) had subsequent disease recurrence, with CD19-negative relapse (n=6) occurring sooner than CD19-positive relapse (P = .0125). With a median follow-up time of 386 days (range 11-1187 days), the EFS for the entire cohort (n = 31) at 6 and 12 months after infusion was 47% (95% confidence interval [CI], 28.4%-63.4%) and 35.2% (95% CI, 18.4%-52.5%), respectively. In multivariate analysis, high pretreatment leukemic burden (≥5% bone marrow blasts) was an independent risk factor for inferior EFS (HR 5.98 [95% CI, 1.1-32.4], P=.0380) and OS (HR 4.2 [95% CI, 1.33-13.39], P=.0148). Tisagenlecleucel induced high initial response rates in a contemporary cohort of pediatric and AYA patients with B-ALL. However, 48% of patients experienced subsequent disease relapse, including 6 with antigen-escape variants. This highlights a considerable limitation of single-agent autologous CD19-CAR T-cell therapy. Pretreatment leukemic disease burden of ≥5% blasts was significantly associated with worse outcomes in this study, including lower EFS and OS. Our findings suggest that reducing preinfusion leukemic burden is a viable treatment strategy to improve outcomes of CAR T-cell therapy.

Cancer care for displaced children in Lebanon.

Lebanon is a small country on the Mediterranean Sea that has been plagued for decades by civil war and internal strife, which result from regional wars and power struggles. Most of the Lebanese population has access to national governmental health-care plans, but these are inadequate to cover the costs of cancer care; therefore, non-governmental organisations (NGOs) are needed to alleviate financial barriers to care. In 2002, the Children's Cancer Institute was established at the American University of Beirut Medical Center (AUBMC; Beirut, Lebanon), as a collaboration between AUBMC, St Jude Children's Research Hospital (SJCRH; Memphis, TN, USA), the Children's Cancer Center of Lebanon Foundation (CCCL; Beirut, Lebanon), and the American Lebanese Syrian Associated Charities (ALSAC; Memphis, TN, USA). This collaboration supports programmatic growth (ie, specific projects aimed at developing medical programmes and services to optimise cancer care and delivery) at the Children's Cancer Institute, and the CCCL and ALSAC ensure that no family pays out-of-pocket expenses for cancer-directed care. Between 2002 and 2012, the Children's Cancer Institute grew to provide care for 35–40% of children with cancer in Lebanon, and consultations or specialised procedures for an additional 20–25%. Networks of paediatric oncologists across the country were established, using funded disease-specific programmes, in which enrolled patients could access centralised diagnosis, specialised surgeries, radiotherapy, and unified treatment plans in coordination with their referring oncologist. Educational attainment in displaced children with cancerSupporting the health of displaced people is a challenge shared by the health system in the location to which they are displaced, non-governmental organisations, and the international community. This challenge is magnified when the host country is struggling with violence, poverty, and an unstable government. The COVID-19 pandemic has added further strain to an already difficult situation, restricting movement both within and between countries. Since 2014, the UN High Commissioner for Refugees has rolled out capacity-building projects in countries hosting displaced people, with the aim of providing access to health care for non-communicable diseases. Full-Text PDF

The Impact of Genetic Ancestry on the Biology and Prognosis of Childhood Acute Lymphoblastic Leukemia

INTRODUCTIONAcute lymphoblastic leukemia (ALL) is the most common cancer in children. Despite improvements in treatment over the past few decades, stark racial disparities persist in disease risk and cure rates. There is a paucity of data describing the genetic basis of these disparities, especially in relation to modern ALL molecular taxonomy and in the context of contemporary treatment regimens. To this end, we sought to determine the associations of genetic ancestry with ALL biology, and the relevance of genetic ancestry to survival outcomes of modern ALL therapy.METHODSThis was a multi-national genomic study of 2,428 children with ALL on front-line trials from United States (St Jude Children's Research Hospital and Children's Oncology Group), South-East Asia (Ma-Spore trials) and Latin America (Guatemala), representing diverse populations of European (EUR), African (AFR), Native American (NA), East Asian (EAS), and South Asian (SAS) descent. We performed RNA-sequencing to characterize ALL molecular subtype, and also estimated their genetic ancestral composition by comparing allele frequencies of patient and reference genomes (1000 Genomes Project reference populations). For categorization of patients into racial groups, individuals were classified based on composition of genetic ancestry as: “white” (EUR >90%), “black” (AFR >70%), “Hispanic” (NA >10% and NA greater than AFR), “East Asian” (EAS >90%), “South Asian” (SAS >70%), with the rest defined as “Other”. We then evaluated the associations of ancestry with ALL molecular subtypes and survival.RESULTSGenetic ancestral composition of the entire cohort is shown in Figure 1A. Of 21 ALL subtypes, 11 showed significant associations with ancestry. Hyperdiploid ALL was most common in white children (30.6%) and the least frequent in blacks (14.4%) (P<0.001). The frequency of ETV6-RUNX1 was highest in blacks (25.6%) and lowest in Hispanics (10.6%) (P<0.001). The DUX4 subtype was markedly more common in Asian children (14.4% of East Asians and 14.8% of South Asians) compared to black children (1.9%) (P<0.001). There was a similar trend for ZNF384 fusion, representing 6.9% of East Asians, compared to 1.7% for whites (P=0.001). TCF3-PBX1 was most prevalent in blacks at 11.9%, with the lowest at 1.7% in whites (P<0.001). PAX5 alteration frequency was highest in South Asians (11.5%) and lowest in whites (4.5%) (P=0.046). CRLF2 rearrangement occurred significantly more frequently in Hispanics (9.0%) and was least common in blacks (1.3%) (P<0.001). BCR-ABL1-like (excluding CRLF2) was also overrepresented in Hispanic children (11.4%), and occurred less frequently in East Asians (4.2%) (P<0.001). MEF2D fusion was most common in blacks (4.4%), and rare in whites (1.4%) and South Asians (0%) (P=0.013). T-ALL differed dramatically in frequency amongst races, especially between blacks and Hispanics with a 7-fold difference (26.5% vs 3.6%, P<0.001). The pattern of ALL subtype in the “Other” racial category generally mirrored that of the dominant ancestral composition, indicating a strong correlation with ancestry even within admixed populations (Figure 1B).We then examined outcomes across racial/ethnic categories. Event-free survival (EFS), overall survival (OS) and cumulative incidence of any relapse (CIR) all differed significantly across population groups (P=0.017 for EFS, P=0.05 for OS, P=0.015 for relapse). White, East Asian and South Asian children overall had more favorable outcomes compared to their black and Hispanic counterparts. Specifically, Hispanics had the poorest 5-year EFS (72.1 ± 4.2 %) and OS (82.3 ± 3.6 %), whereas South Asians had the highest EFS (94.6 ± 3.6 %) and OS (98.2 ± 2.1 %). Relapse risk trended in parallel with that of EFS and OS, with South Asians having one of the lowest CIR of 3.7 ± 2.6 %, and Hispanics having the highest at 22.8 ± 2.9 %. We repeated the analysis with genetic ancestry as a continuous variable and obtained largely similar results. Importantly, even after adjusting for biological subtypes and clinical features, Native American and African ancestries remained independently associated with poor prognosis.CONCLUSIONSALL biology and prognosis are highly associated with genetic ancestry, pointing to a genetic basis for racial disparities in ALL. Biology-driven treatment individualization is needed to eliminate racial gaps in the cure of this cancer. [Display omitted] DisclosuresEvans: Princess Máxima Center for Pediatric Oncology, Scientific Advisory Board, Chair: Membership on an entity's Board of Directors or advisory committees; BioSkryb, Inc.: Membership on an entity's Board of Directors or advisory committees; St. Jude Children's Research Hospital, Emeritus Member (began Jan 2021): Ended employment in the past 24 months. Mullighan: Illumina: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Pfizer: Research Funding; Amgen: Current equity holder in publicly-traded company. Loh: MediSix therapeutics: Membership on an entity's Board of Directors or advisory committees. Yeoh: Amgen: Honoraria, Other: Chair, Steering Committee for ALL Academy in South East Asia. Pui: Novartis: Other: Data Monitoring Committee; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees.

Mapping the Glucocorticoid Gene Regulatory Network and Alterations That Contribute to Steroid Resistance in Childhood Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer and despite improved survival rates, relapsed ALL is still among the most common causes of cancer death in children. Although changes in the expression of specific genes have been linked to chemotherapeutic resistance, relatively little is understood of the pharmacogenomic impact of the noncoding, cis-regulatory landscape governing gene regulation. Glucocorticoids (GCs; i.e. steroids) are a mainstay of contemporary, multi-drug chemotherapy in ALL, and GC resistance is predictive of both relapse and poor clinical outcome in ALL. Because GCs function through activation of glucocorticoid receptor (GR), a nuclear receptor transcription factor that interacts directly with cis-regulatory elements, unveiling the glucocorticoid gene regulatory network (GC-GRN) in leukemia cells is crucial to understanding not only the biological mechanism of apoptosis, but also illuminating gene regulatory mechanisms contributing to GC resistance. To test the hypothesis that alterations to the GC-GRN are important contributors to steroid resistance in ALL, we comprehensively mapped cellular responses to GCs in human ALL cell lines using >100 independent functional genomic datasets. This comprehensive approach uncovered thousands of genes and cis-regulatory elements that were responsive to GCs, and further identified >38,000 high-confidence glucocorticoid response elements (GREs) in the ALL genome. A closer examination of these data revealed GR binding profiles that were consistent with the long-range flexible billboard model of gene regulation. By further integrating our results with genetic and epigenetic data in primary ALL cells from patients enrolled on St. Jude clinical trials, we identified 45 DNA sequence variants associated with ex vivo GC resistance that map to GREs and functionally validated an associated variant within the TLE1 gene locus. We also uncovered 1929 accessible chromatin sites (FDR<0.1) in primary ALL cells that were associated with ex vivo GC resistance, and these GC-resistance accessible chromatin sites were highly enriched at GREs determined from ALL cell lines (p<2.2x10 -16). High-throughput pharmacogenomic CRISPRi screening in human ALL cell lines with a library of >10,000 sgRNAs targeting >1000 GR binding events at putative GC-resistance accessible chromatin sites identified a subset of GR binding sites implicated in GC resistance. Overall, these data indicate that GCs initiate pervasive, genome-wide effects on the leukemia epigenome and transcriptome, and that genetic and epigenetic alterations to GREs are mechanisms contributing to GC resistance in childhood ALL. DisclosuresPui: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Data Monitoring Committee. Evans: Princess Máxima Center for Pediatric Oncology, Scientific Advisory Board, Chair: Membership on an entity's Board of Directors or advisory committees; BioSkryb, Inc.: Membership on an entity's Board of Directors or advisory committees; St. Jude Children's Research Hospital, Emeritus Member (began Jan 2021): Ended employment in the past 24 months.

Vitamin D Levels: Associations with Acute Pain Events and Self-Reported Pain in Children with Sickle Cell Disease

Background/Aims: Individuals with sickle cell disease (SCD) are at high risk for vitamin D deficiency due to dark skin color, limited physical activity, poor nutrition, and renal dysfunction. In smaller retrospective studies, vitamin D deficiency in SCD was associated with increased frequency of acute pain events and higher opioid use, however the impact of vitamin D deficiency on pain related patient reported outcomes has not been described . Supplementation with high dose vitamin D is shown to be associated with fewer pain days per week and higher physical activity scores in patients with chronic pain. Thus, the objective of our study was to evaluate relationship between vitamin D levels, acute health care utilization and self-reported pain among children with SCD. We hypothesized that vitamin D deficiency is associated with increase health care utilization for pain and patient-reported outcomes for pain.Methods: Patients with SCD (1 to 18 years of age), enrolled in Sickle Cell Clinical Research and Intervention Program (SCCRIP), at St. Jude Children's Research Hospital were included in the study (Hankins et.al., Pediatric Blood and Cancer, 2018). Demographic, clinical and laboratory data were extracted from SCCRIP database. Prospective pain event leading to a hospital visit was analyzed. We analyzed pain-related hospitalizations in two ways: the number of pain-related hospitalizations within 2 years prior to and after vitamin D measurement in a cross-sectional design and longitudinally. Generalized linear regression model was used to examine associations between vitamin D and cross-sectional pain events with adjusting for hydroxyurea use. Generalized linear mixed effect model was used to assess the associations between vitamin D and longitudinal pain events, with adjusting for SCD genotype, sex, age, hydroxyurea use and interaction between age and hydroxyurea use.Pediatric Quality of Life Inventory™ Sickle Cell Disease Module (PedsQL™ SCD) was used to measure pain and pain interference using 1) Pain and Hurt and 2) Pain Impact scales. PedsQL™ SCD assessments include a Likert response scale. Items are reverse -scored and transformed to a 0-100 scale where higher scores indicate better health related quality of life in that scale. Two sample t-test or Wilcoxon rank sum test was used to compare mean scores between the two groups.Results: A total of 799 patients (females, n=398; males, n=401) were included in the study. Mean age (Standard Deviation [SD]), range at time of first vitamin D measurement for entire cohort was 8.7 (4.7), (0.8-18 years). Mean (SD) initial vitamin D level for entire cohort was 19.0 (9.4) ng/dl. Mean (SD) number of pain-related hospitalizations within two years of first vitamin D measurement was higher in the vitamin D deficient group as compared to non deficient group [0.81(1.97) vs 0.66 (1.2), (p=0.0034)]. Longitudinal data analyses showed vitamin D deficiency was associated with increased number of pain related hospitalizations (p=0.0091), after adjusting for covariates listed above (Figure 1a).Mean (SD) scores for Pain and Hurt in vitamin D deficient versus non deficient group were [74.5.7(18.2) versus 83.5(15.6), p < 0.001]. Mean (SD) scores for Pain Impact in vitamin D deficient group as compared to non deficient group were [(66.7 (22.7) versus 75.5 (22.3), p <0.001] (Figure 1b)Conclusion: Results indicated that low vitamin D levels predicted higher frequency of painful events leading to a hospital visit and were associated with higher prevalence of self-reported pain and pain interference. Further studies evaluating mechanisms by which vitamin D influences sickle cell pain are warranted and larger controlled trials can help evaluate the therapeutic efficacy of vitamin D for sickle cell pain. [Display omitted] DisclosuresHankins: UpToDate: Consultancy; Bluebird Bio: Consultancy; Vindico Medical Education: Consultancy; Global Blood Therapeutics: Consultancy.

Clofarabine-Based Chemotherapy for KMT2Ar Infantile Acute Lymphoblastic Leukemia

Rearrangements in KMT2A (KMT2Ar) are associated with pediatric, adult and therapy-induced acute leukemias. Infants with KMT2Ar acute lymphoblastic leukemia (ALL) have a poor prognosis, with an event-free-survival (EFS) of 33.6-36.9%. In the context of the remarkable improvements in the treatment of childhood ALL, the dismal outcome of infantile KMT2Ar ALL and the lack of any significant progress for more than two decades are striking . The St. Jude Total Therapy 16 study (the most recently reported study of a program for childhood ALL that begun in 1962) yielded a 5-year EFS of 88.2% overall. Total 16 enrolled all subtypes of newly diagnosed pediatric ALL patients including infants, with intensity of treatment adapted to presenting clinical and genomic features, and early treatment response as determined by minimal/measurable residual disease (MRD). KMT2Ar infants were treated on an intensified high-risk arm and received clofarabine in combination with cyclophosphamide and etoposide (CCE) at two points during treatment: Induction days 22-25 and Reinduction I. Infants who lacked KMT2Ar and KMT2Ar patients who were one year of age or older received the same risk-directed treatment plan given to all other patients enrolled on study. A total of 28 patients with KMT2Ar were enrolled on Total 16; the 19 patients > 1 year of age received standard-risk therapy, and the 9 patients < 1 year of age received high-risk therapy on the infant arm with CCE. The probabilities of 5-year EFS and overall survival in KMT2Ar patients > 1 year of age and those < 1 year of age were 73.3% vs. 44.4% (p=0.071) and 84.2% vs. 55.6% (p=0.060), respectively. Six of the nine infants were MRD-positive on Induction day 15 prior to CCE (MRD-positive range, 0.012% to 13.7%; median, 2.13%) with MRD negative status (<0.01%) achieved post CCE in six of the eight patients with data (MRD was 0.011% and 0.07% in the remaining two patients). The trend towards superior outcomes in older KMT2Ar patients was not due to a lower incidence of relapse, as the 5-year cumulative incidence of relapse was 26.7% in patients > 1 year of age and 12.5% for those < 1 year of age (p=0.454). Five infants remain alive (four in CR1, one in CR2), while four expired in CR1. Three deaths were secondary to infection, including a multi-drug resistant soft tissue bacterial infection during Induction days 1-21, a respiratory syncytial virus pneumonia during Reinduction II, and a chronic parainfluenza 3 infection during Continuation weeks 70-101 that led to chronic pneumonitis and interstitial fibrosis. The fourth patient developed grade 5 pulmonary hypertension following induction, a complication potentially compounded by their presenting WBC count of 905 x 10 9/L and pulmonary leukostasis. A comparison of 3-year cumulative risk of selected major toxic effects of treatment revealed that high-risk infants had a lower incidence of asparaginase allergic reactions, osteonecrosis, hyperglycemia, and pancreatitis; in contrast, the incidence of fever and neutropenia, hepatic toxicity and seizures, was similar in high-risk patients regardless of age. Infants had a higher risk of thrombosis (46.7% vs. 23.1%, p<0.001) and of severe infection (70% vs. 19.7%, p<0.001). To further study the contribution of clofarabine to severe infections, we looked at the incidence in high-risk patients > 1 year of age that received one or more clofarabine-containing Reintensification chemotherapy cycles prior to hematopoietic stem cell transplant in first remission (CR1). This revealed a higher frequency of infections in infants, suggesting a greater susceptibility to this complication independent from clofarabine exposure (mean number of episodes, 2.39 vs. 1, p<0.001, Poisson regression modeling). In conclusion, treatment of infants with KMT2Ar ALL with chemotherapy including high-intensity clofarabine leads to a lower cumulative incidence of relapse but a higher risk of treatment-related mortality. Severe infections were a major cause of morbidity and mortality. DisclosuresGruber: Kura Oncology: Consultancy. Coustan-Smith: Juno Therapeutics: Patents & Royalties; Nkarta Therapeutics: Current holder of individual stocks in a privately-held company; Medisix Therapeutics: Current holder of individual stocks in a privately-held company. Campana: Nkarta Therapeutics: Current holder of stock options in a privately-held company; Medisix Therapeutics: Current holder of stock options in a privately-held company; Juno: Other: patent licensing payments; Juno Therapeutics (a Bristol-Myers Squibb company),: Other: patents on methods for minimal residual disease detection.. Evans: St. Jude Children's Research Hospital, Emeritus Member (began Jan 2021): Ended employment in the past 24 months; BioSkryb, Inc.: Membership on an entity's Board of Directors or advisory committees; Princess Máxima Center for Pediatric Oncology, Scientific Advisory Board, Chair: Membership on an entity's Board of Directors or advisory committees. Pui: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Data Monitoring Committee.

Amino Acid Stress Response Genes Promote L-Asparaginase Resistance in Pediatric Acute Lymphoblastic Leukemia

▪Understanding the genomic and epigenetic mechanisms of drug resistance in pediatric acute lymphoblastic leukemia (ALL) is critical for further improvements in treatment outcome. The role of transcriptomic response in conferring resistance to l-asparaginase (LASP) is poorly understood, beyond asparagine synthetase (ASNS). We defined reproducible LASP response genes in LASP resistant and sensitive ALL cell lines (n = 7) as well as primary leukemia samples from newly diagnosed patients. We identified 2219 response genes (absolute log 2FC > 1.5, FDR p-value <0.05) with ~16.5% being reproduced in more than one cell line. Defining target genes of the amino acid stress response related transcription factor ATF4 in ALL cell lines using ChIP-seq revealed 25% of genes that changed expression after LASP treatment were direct targets of the ATF4 transcription factor. A total of 17,117 significantly differentially bound ATF4 sites were identified (FDR p-value <0.01) and 97.8% of these sites displayed an increase in ATF4 binding following LASP treatment. SLC7A11 was found to be a response gene in cell lines and patient samples as well as a direct target of ATF4. SLC7A11 was also one of only 2.4% of response genes with basal level gene expression that also correlated with LASP ex vivo resistance in primary leukemia cells from 212 newly diagnosed children enrolled on St. Jude Total Therapy 16. Experiments using chemical inhibition of SLC7A11 with sulfasalazine, gene overexpression, and partial gene knockout recapitulated LASP resistance or sensitivity in ALL cell lines. These findings show the importance of assessing changes in gene expression following treatment with an antileukemic agent for its association with drug resistance and highlights that many response genes may not differ in their basal expression in drug resistant leukemia cells. DisclosuresStock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Mullighan: Amgen: Current equity holder in publicly-traded company; Illumina: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Pfizer: Research Funding. Pui: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Data Monitoring Committee. Evans: Princess Máxima Center for Pediatric Oncology, Scientific Advisory Board, Chair: Membership on an entity's Board of Directors or advisory committees; BioSkryb, Inc.: Membership on an entity's Board of Directors or advisory committees; St. Jude Children's Research Hospital, Emeritus Member (began Jan 2021): Ended employment in the past 24 months.

A Phase II Study of Prophylactic Anakinra to Prevent CRS and Neurotoxicity in Patients Receiving CD19 CAR T Cell Therapy for Relapsed or Refractory Lymphoma

A Phase II Study of Prophylactic Anakinra to Prevent CRS and Neurotoxicity in Patients Receiving CD19 CAR T Cell Therapy for Relapsed or Refractory Lymphoma

The Intestinal Microbiota Correlates with Response and Toxicity after CAR T Cell Therapy in Patients with B-Cell Malignancies

The Intestinal Microbiota Correlates with Response and Toxicity after CAR T Cell Therapy in Patients with B-Cell Malignancies

Vitamin A and D Levels Correlate with Outcomes Following Acute Parvovirus B19 Infection in Children with Sickle Cell Disease

Background: Human parvovirus B19, a common childhood infection that typically causes mild disease in healthy individuals, causes life-threatening anemia due to transient red cell aplasia (aplastic crisis) in individuals with sickle cell disease (SCD). This complication often leads to hospitalization and red blood cell transfusions. Limiting the amount of transfusions is imperative to avoid alloimmunization. Strategies to mitigate complications from parvovirus B19 or reduce disease severity in SCD patients are needed. In this prospective observational study, we aim to describe the relationship between vitamin A and D levels and severity of symptoms during parvovirus B19 infection in pediatric patients with SCD.Methods: Twenty pediatric patients with SCD admitted to St. Jude Children's Research Hospital experiencing aplastic crisis and identified as having an active parvovirus B19 infection were under an IRB approved protocol (NCT02261480) and followed prospectively for 120 days post-infection. Acute parvovirus B19 infection was diagnosed by fever and a positive virus-specific IgM ELISA or PCR. Aplastic crisis was defined by worsened anemia without sufficient compensatory reticulocytosis in the setting of an acute parvovirus B19 infection. Virus-specific antibody responses were measured from sera or nasal washes (NW) by ELISA using parvovirus B19 virus-like particles (VLP) as target antigens. Peak serum antibody titers were defined (among measurements from Days 0, 7, 30, and 120). Total erythrocyte transfusion volumes required during the admission were quantified. Hematologic indices and vitamin A and D levels were obtained on Day 0. Vitamin A (retinol) was measured using UPLC and vitamin D (25[OH]D) was measured using a Roche Elecsys Vitamin D ELISA. Statistical analyses were performed with Spearman's rank correlation coefficient or Mann Whitney tests. We scored significance as p<0.05.Results: Twenty patients with different genotypes of SCD requiring hospital admission due to acute parvovirus B19 infection were sequentially enrolled (15 HbSS, 3 HbSC, 1 HbSD, 1 HbSβeta +thalassemia). Thirty-five percent (7/20) of patients were vitamin D deficient (VDD, defined here as <20 ng/mL) while 89% (17/19, one sample was not measured) of patients were marginally or severely vitamin A deficient (defined here as <20 μg/dL) on Day 0. Correlative analyses between vitamin levels and markers of disease severity are shown in figure 1. Lower vitamin D levels trended with lower hemoglobin (r=0.399, p=0.082) and there was a significant inverse correlation between transfused volume and vitamin D levels (r=-0.626, p=0.003, Figure 1B). There was a significant positive correlation of vitamin A levels on Day 0 with hemoglobin concentration (r=0.549, p=0.015, Figure 1D), and an inverse correlation between vitamin A levels and lactate dehydrogenase (r=-0.505, p=0.027, Figure 1F).Children with replete vitamin D levels exhibited significantly better peak virus-specific serum IgG (p=0.037) and IgA (p=0.011) responses (Figure 2A-B). Additionally, vitamin A, which plays an important role in mucosal immunity, correlated positively with virus-specific IgG (r=0.574, p=0.013) and IgA (r=0.480, p=0.044) in nasal passages on Day 30 (Figure 2C-D).Conclusions: In pediatric patients admitted to the hospital for acute parvovirus B19 infection, low vitamin A and D levels were associated with greater disease severity (greater hemolysis, lower hemoglobin concentration, and greater transfusion volumes). Higher vitamin levels were associated with better virus-specific antibody responses. While cause-effect relationships were not discerned in this study, we hypothesize that poor nutritional status contributed to poor outcomes and that efforts to improve nutrition may reduce the severity of parvovirus B19 disease in patients with SCD. [Display omitted] DisclosuresHankins: UpToDate: Consultancy; Vindico Medical Education: Consultancy; Global Blood Therapeutics: Consultancy; Bluebird Bio: Consultancy.

"IF-Better" Gating: Combinatorial Targeting and Synergistic Signaling for Enhanced CAR T Cell Efficacy

Abstract CAR T cell therapy provides a potent therapeutic option in various B cell-related hematologic malignancies. One of the major efficacy challenges is escape of tumor cells with low antigen density, which has been clinically observed in several malignancies treated with CAR therapy. Novel concepts of CAR design are needed to address phenotypic heterogeneity including clonal variability of target antigen expression. In the study presented here, we focused on AML and selected ADGRE2 as CAR target due to its high rate of positivity on AML bulk and leukemic stem cells (LSC) in a molecularly heterogeneous AML patient population. We chose an ADGRE2-CAR with optimized scFv affinity and fine-tuned CD3zeta signaling to achieve an ideal killing threshold that would allow for sparing of ADGRE2-low normal cells. We hypothesized that co-targeting of a second AML-related antigen may mitigate potential CAR target antigen-low AML escape and we identified CLEC12A as preferential co-target due to its non-overlapping expression profiles in normal hematopoiesis and other vital tissues. We developed ADCLEC.syn1, a novel combinatorial CAR construct consisting of an ADGRE2-targeting 28z1XX-CAR and a CLEC12A-targeting chimeric costimulatory receptor (CCR). ADCLEC.syn1 operates based on what we describe as "IF-BETTER" gate: High CAR target expression alone triggers killing, whereas low CAR target expression does not, unless a CCR target is present. Additional CCR interaction lowers the threshold for CAR-mediated killing through increased avidity and costimulation, allowing for higher CAR sensitivity that is purposefully limited to target cells expressing both antigens. In the context of ADCLEC.syn1, ADGRE2-high/CLEC12A-negative AML cells can trigger cell lysis while ADGRE2-low/CLEC12A-negative normal cells are spared. Importantly, ADGRE2-low/CLEC12A-high AML cells are also potently eliminated, preventing ADGRE2-low AML escape. Using NSG in-vivo xenograft models of engineered MOLM13 AML cell line variants with low levels of ADGRE2 to model antigen escape, we found that ADCLEC.syn1 outperforms a single-ADGRE2-CAR lacking assistance via CLEC12A-CCR. Importantly, ADCLEC.syn1 also outperformed an otherwise identical alternative dual-CAR version (OR-gated ADGRE2-CAR+CLEC12A-CAR) in the setting of both ADGRE2-high and ADGRE2-low MOLM13, further underlining the importance of fine-tuned overall signaling. We confirmed high in-vivo potency against diverse AML cell lines with a wide range of ADGRE2 and CLEC12A levels reflecting population-wide AML heterogeneity. At clinically relevant CAR T cell doses, ADCLEC.syn1 induced complete and durable remissions in xenograft models of MOLM13 (ADGRE2-high/CLEC12A-low) and U937 (ADGRE2-low/CLEC12A-high). ADCLEC.syn1 CAR T cells were found to be functionally persistent for &amp;gt;70 days, with a single CAR T cell dose potently averting relapse modeled via AML re-challenges. In summary, we provide pre-clinical evidence that an "IF-BETTER"-gated CAR+CCR T cell (ADCLEC.syn1) can outperform a single-CAR T cell (ADGRE2-CAR) and a dual-CAR T cell (ADGRE2-CAR+CLEC12A-CAR). ADCLEC.syn1 enhances antileukemic efficacy and prevents antigen-low AML escape via detection of a rationally selected combinatorial target antigen signature that is commonly found in AML but limited in vital normal cells. Using phenotypically representative AML xenograft models and clinically relevant T cell doses, we demonstrate high therapeutic potential of ADCLEC.syn1 CAR T cells, further supporting clinical translation of an "IF-BETTER"-gated CAR concept into a phase 1 trial. Disclosures Haubner: Takeda Pharmaceuticals Company Ltd.: Patents &amp; Royalties: Co-inventor of IP that MSK licensed to Takeda, Research Funding. Mansilla-Soto: Takeda Pharmaceuticals Company Ltd.: Patents &amp; Royalties; Atara Biotherapeutics: Patents &amp; Royalties; Fate Therapeutics: Patents &amp; Royalties; Mnemo Therapeutics: Patents &amp; Royalties. He: Takeda Pharmaceuticals Company Ltd.: Ended employment in the past 24 months, Patents &amp; Royalties. Park: Curocel: Consultancy; BMS: Consultancy; Innate Pharma: Consultancy; Autolus: Consultancy; Servier: Consultancy; Kite Pharma: Consultancy; Affyimmune: Consultancy; Intellia: Consultancy; Minerva: Consultancy; PrecisionBio: Consultancy; Amgen: Consultancy; Kura Oncology: Consultancy; Artiva: Consultancy; Novartis: Consultancy. Rivière: Juno Therapeutics: Patents &amp; Royalties; Fate Therapeutics: Other: Provision of Services, Patents &amp; Royalties; Centre for Commercialization of Cancer Immunotherapy: Other: Provision of Services; The Georgia Tech Research Corporation (GTRC): Other: Provision of Services (uncompensated); FloDesign Sonics: Other: Provision of Services. Sadelain: NHLBI Gene Therapy Resource Program: Other: Provision of Services (uncompensated); St. Jude Children's Research Hospital: Other: Provision of Services; Minerva Biotechnologies: Patents &amp; Royalties; Mnemo Therapeutics: Patents &amp; Royalties; Juno Therapeutics: Patents &amp; Royalties; Fate Therapeutics: Other: Provision of Services (uncompensated), Patents &amp; Royalties; Ceramedix: Patents &amp; Royalties; Takeda Pharmaceuticals: Other: Provision of Services, Patents &amp; Royalties; Atara Biotherapeutics: Patents &amp; Royalties.

MTHFR and SLCO1B1 Gene Polymorphism and Methotrexate Induced Toxicity in Children with Acute Lymphoblastic Leukemia in the Northwest of Mexico

Introduction.Acute lymphoblastic leukemia (ALL) represents approximately 52% of pediatric cancer diagnoses in Mexico and is the leading cause of death by disease among children of 5 to 14 years. The use of pharmacogenomics for the detection of germline genetic variations, which are associated with sensitivity or toxicity to chemotherapy, is one of the recent strategies to improve survival. Some mutations present in genes related to the metabolism or transport of methotrexate (MTX) have been associated with the occurrence of toxicities during treatment in pediatric acute lymphoblastic leukemia. The effect of the SNP´s rs1801131, rs1901133 in the MTHFR and rs4149058, rs4149081 in the SLCO1B1 gene have not been studied in Northwest Mexican children with acute lymphoblastic leukemia.Patients and methods.Eligible patients were infants less than 1 year to adolescents less than 18 years of age, diagnosed with B-ALL at the Specialties Children's Hospital of Chihuahua, Mexico. Patients were treated according to the locally protocols based on the St. Jude Children's Research Hospital Total XIIIB and Total XV protocols. We followed-up for two to four weeks after 24 hours high dose MTX (1 to 5 g/m 2) administration. Toxicity data were collected objectively from the patient's medical files and adverse effects were classified as a dichotomous variable yes/no. Genomic DNA was extracted with the Master Pure DNA purification kit (Epicentre Illumina® Company) from peripheral blood. Genotyping assays were performed by real-time polymerase chain reaction, using rhAMp® IDT® genotyping probes (Iowa, USA) and Quant Studio 3 Applied Biosystems Real-Time System Thermal Cycler (Thermo Fisher Scientific®). For statistical analysis association between MTX dose, presence of toxicity, and genetic polymorphisms was evaluated by the chi-square or Fisher's exact test. The effect sizes of the associations were estimated by the OR's from univariate logistic regressions and multivariate logistic regressions to account for the possible confounding effect of sex and age. Analyses were performed by using SAS System and IBM SPSS Statistics Base 22.0 software.Results.The study population demographics and clinical characteristics are summarized in Table 1. MTHFR and SLCO1B1 genotype in our patients and controls obtained from the 1000 Genomes Project database are shown in table 2. In general, a predominance of toxicity events is observed in patients heterozygous for both polymorphisms in the MTHFR gene, but not in the SLCO1B1 gene (Figure 1). Through a logistic regression analysis, we observed an association of 8% between the polymorphisms rs1801131, rs1901133, rs4149058, rs4149081 and the presence of anemia. The AC heterozygous of the rs1801131 has the strongest association with a positive coefficient (+1.1355) and when comparing AC heterozygotes with CC mutated homozygotes, an Odds Ratio (OR) of 4.64 (CI: 95%, 0.719) was observed, identifying it as a risk factor. In contrast, the homozygous AA of the same gene, presented a negative coefficient (-0.7354), thus decreasing the probability of presenting anemia in this population. The presence of neutropenia was associated in 25% with the polymorphisms rs1801131, rs1901133, rs4149058, rs4149081. The AA homozygous of rs1801131 decreased the probability of developing neutropenia (coefficient -0.7643, p=0.04) and the TC heterozygous of rs4149056 increased the probability when comparing with the wild TT homozygotes (OR of 2.91, CI: 95%, 0.496). Liver enzymes elevation was associated in 84% with the polymorphisms rs1801131, rs1901133, rs4149058, rs4149081. We found that the presence of TC heterozygote of rs4149056 decreased the probability of hepatotoxicity (coefficient -1.5718, p=0.03) and GA heterozygote of rs41419081 increased it (coefficient +3.2056, p=0.004) (Table 3). According to this statistical model, we could not analyze the association between the polymorphisms rs1801131, rs1901133, rs4149058, rs4149081 and thrombocytopenia, mucositis, febrile neutropenia or creatinine elevation.ConclusionToxicity related to treatment is one of the most important causes of death among pediatric ALL patients in Mexico, the development of precision medicine through the identification of SNPs associated with the variability in our patients' response is an alternative to minimize methotrexate toxicity and maximize its benefit during its use. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Chromatin Accessibility Landscapes of Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common malignancy in pediatric patients spanning both B- and T-cell lineages. ALL also occurs less commonly in adults but with cure rates of only around 30%. Past work has characterized ALL into molecular subtypes spanning a range of aberrant chromosomal rearrangements and oncogene chimeric fusions driving malignancy. While transcriptional profiling of these subtypes has been extensively examined, the accompanying chromatin accessibility landscape and corresponding gene regulatory repertoire is not well characterized for many subtypes. To better profile the ALL epigenomic and gene regulatory repertoire we examined chromatin accessibility of 12 distinct molecular subtypes (BCR-ABL1, ETV6-RUNX1, Hyperdiploid, Hypodiploid, KMT2A rearranged, Ph-Like, PAX5, DUX4/ERG, TCF3-PBX1, T-ALL, Early T Precursor and B-other) across 189 primary patient samples of pediatric ALL (n = 106) and adult ALL (n = 83) origin using ATAC-seq. To our knowledge, this represents the largest collection of chromatin accessibility data in primary ALL samples spanning multiple molecular subtypes to date. Collectively, we identified over 600,000 accessible chromatin sites in the ALL genome with over 50,000 regions of differentially accessible chromatin encompassing both common and subtype-specific modalities. Further, transcription factor (TF) footprint profiling of ATAC-seq yielded tens of thousands of candidate TF binding events and identified key TF drivers within distinct molecular subtypes. We additionally performed H3K27ac ChIP-seq in a subset of 12 primary ALL patient samples, with integration of these histone data for select patient samples allowing inferences about candidate super-enhancer drivers of ALL molecular subtypes. Overall, these analyses and data offer a window into the gene regulatory and epigenetic landscape of ALL, and further highlight the complexity and heterogeneity of accessible chromatin landscapes among distinct molecular subtypes of ALL. DisclosuresStock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Pui: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Data Monitoring Committee. Evans: Princess Máxima Center for Pediatric Oncology, Scientific Advisory Board, Chair: Membership on an entity's Board of Directors or advisory committees; St. Jude Children's Research Hospital, Emeritus Member (began Jan 2021): Ended employment in the past 24 months; BioSkryb, Inc.: Membership on an entity's Board of Directors or advisory committees.

Synergism between CAR-T Cells and a Personalized Tumor Vaccine in Hematological Malignances

Synergism between CAR-T Cells and a Personalized Tumor Vaccine in Hematological Malignances

Optimization of Autologous Hematopoietic Progenitor Stem Cell Apheresis Collection from Plerixafor-Mobilized Patients with Sickle Cell Disease

IntroductionAutologous hematopoietic progenitor cell (HPC)-based gene therapy and genome editing are emerging therapeutic strategies for patients with sickle cell disease (SCD). Given the high cell loss incurred during production of genetically modified HPCs, a large number of HPCs (10-15 x10 6 cells/kg) are required. Obtaining sufficient autologous HPCs from patients with SCD is a critical rate limiting step for the success of these novel genetic therapies. Plerixafor, a CXCR4 antagonist, has been shown to be safe and efficient for HPC mobilization in patients with SCD. However, impaired red blood cell (RBC) rheology and chronic inflammation associated with SCD make HPC apheresis collection challenging. For example, HPCs can potentially form aggregates with sickled RBCs traveling deep in the buffy coat upon density-based separation. In addition, elevated levels of activated platelets can increase cell clumping during apheresis. Thus, autologous HPC collection using standard apheresis setting is generally less efficient in patients with SCD and often associated with clumping and unstable cell interfaces during apheresis. It has been reported that standard HPC apheresis collections yield <0.7 x 10 6 CD34+ cells/kg per procedure in SCD patients despite adequate HPC mobilization (peak CD34 count 36-65/µL; Esrick, EB et al., 2018). To address these challenges, we modified our apheresis collection settings to improve the HPC collection efficiency and yield from plerixafor-mobilized patients with SCD.MethodsAdult patients with SCD who were enrolled on two clinical trials (NCT03226691 and NCT04443907) at St. Jude Children's Research Hospital and the National Heart, Lung and Blood Institute at the National Institutes of Health were included. Hydroxyurea was discontinued at least 2 weeks and an RBC exchange was performed 3-7 days prior to HPC mobilization. The participants received 240 µg/kg of Plerixafor subcutaneously, and underwent HPC collection 2-4 hours later using the Spectra Optia continuous mononuclear cell collection. Acid-citrate-dextrose-solution A was used for anticoagulation and calcium gluconate was infused during apheresis to prevent citrate-induced hypocalcemia symptoms. Up to 4 total blood volumes were processed for each collection with an adjusted collection preference (CP) of 10-40 and AC/Inlet ratio of 6-12. Collection efficiency (CE) 1 was calculated as CD34+ cell yield / [(pre-CD34 count + post-CD34 count)/2 x whole blood volume processed]. CE 2 was calculated as CD34+ cell yield / (pre-CD34 count x whole blood volume processed).ResultsWe performed 46 autologous HPC collections in 26 participants (age of 20 to 50 years). Mean (±1SD) pre-collection blood indices were: hematocrit (Hct) 27.4 ±3.8%, platelet count 226 ± 111 x10 9/L, and hemoglobin S 25.7 ± 6.0%, WBC count 13.82 ± 6.0 x10 9/L, and CD34+ cell count 62 ± 49 /µL. To address the altered HPC sedimentation and clumping associated with SCD, we targeted a deep buffy coat collection by lowing CP from standard 50 to 10-40, and used more anticoagulant by lowering Inlet/AC ratio from standard 12 to 6-12 respectively. The adjustments increased HPC yield, and 5.60 ± 5.48 x10 6/kg CD34+ cells were collected per procedure. The CE1 was 49.21 ± 28.34 % and CE2 42.74 ± 26.24%, which are comparable to autologous HPC CEs for non-SCD individuals. A deep collection led to highly efficient collections, although this tended to increase RBC contamination of the products (product Hct 6.0 ±2.2% versus < 3% for standard collection). Nevertheless, the participants experienced minimal loss of RBCs with a post-collection Hct of 26.6 ± 2.9%. Platelet loss was also relatively low, as demonstrated by a post-collection platelet count of 152 ± 69 x 10 9/L. No participants required platelet or blood transfusions, had bleeding or severe hypocalcemia-associated symptoms during and after the collections.ConclusionThe adjusted apheresis settings with a low buffy coat collection and increased anticoagulant dosage allowed safe and efficient autologous HPC collection in the patients with SCD. Further optimization of apheresis settings is required to increase HPC collection efficiency. DisclosuresSharma: Novartis: Other: Salary support paid to institution; Spotlight Therapeutics: Consultancy; Medexus Inc: Consultancy; CRISPR Therapeutics: Other, Research Funding; Vindico Medical Education: Honoraria; Vertex Pharmaceuticals/CRISPR Therapeutics: Other: Salary support paid to institution. Hankins: Bluebird Bio: Consultancy; UpToDate: Consultancy; Vindico Medical Education: Consultancy; Global Blood Therapeutics: Consultancy. Weiss: Cellarity Inc.: Consultancy; Novartis: Consultancy; Forma Therapeutics: Consultancy; Beam Therapeutics: Current holder of stock options in a privately-held company.

A rare blood disorder that created a watercolour storytelling movement

Hereditary elliptocytosis; those are the two words that echoed through the room of St Jude Children's Research Hospital (Memphis, TN, USA) in the mid 80s to my parents. I was diagnosed with hereditary elliptocytosis after a few short years of genetic blood tests throughout my family. I was always an artsy child growing up—active in ballet, painting, and tap dance. My mother, who was a nurse at the time, noticed reoccurring jaundice in my eyes as well as unusual fatigue for a newborn. With a low haematocrit at just 1 month of age, my paediatrician immediately started mentioning options for a blood transfusion.

Long term survival outcome of childhood acute lymphoblastic leukemia treated with modified TXIIIB protocol at South Egypt Cancer Institute

Background: The survival of children with acute lymphoblastic leukemia (ALL) has greatly improved in recent decades. Aim: We aimed at evaluating the outcome of children with ALL and their prognostic factors. Materials & Methods: A prospective study included 200 newly diagnosed pediatric ALL patients from 2009 to 2017. All patients were treated according to the modified total therapy study XIIIB for higher risk ALL adopted from St. Jude Children's Research hospital (SJCRH), USA. Results: Favorable age (< 10 y) and total leucocytic count (TLC) (≥ 50x109/L) occurred in 75% and 69%, respectively. B-precursor ALL represented 82.5%. Central nervous system (CNS) involvement occurred in 4.5%. High-risk patients represented 47%. Complete remission was achieved in 92.5% and was significantly affected by the early morphologic response of BM d15, while it wasn’t related to the phenotype. Eight- year overall survival, disease-free survival, and event-free survival were 77 ± 3%, 70 ± 4%, and 66 ± 3%, respectively. Adverse events included induction deaths (4.5 %(, refractory leukemia (3%), relapse (23.2%), secondary AML (0.5%), and deaths in remission (3.5%). By multivariate analysis, unfavorable age group ≥ 10 years, hyperleukocytosis, and patients with slow early response were the only ones associated with unfavorable impact on the outcome. There was statistical significant difference between standard and high risk for B-precursor ALL but not for T- precursor ALL. Conclusion: We concluded that treating children with ALL through modified TXIIIB protocol improved the survival at our institute than previous and the early response to treatment has a strong implication on the outcome.

Research progress of CTCF in mediating 3D genome formation and regulating gene expression.

In interphase eukaryotic nuclei, chromatin is folded to form a higher-order topological structure. The spatial organization of such chromatin domain has an important impact on the regulation of gene expression. As a key architectural structural protein, CTCF (CCCTC-binding factor) plays an important role in the formation of chromatin three-dimensional chromatin structure. CTCF can also bind to many insulator elements in the genome and insulate enhancers from activating target genes via modulating remote chromatin interactions. A recent study by Dr. Chunliang Li and his team at St. Jude Children's Research Hospital in the United States showed that when CTCF was acutely degraded, significant changes were found in the three-dimensional structure of chromatin. The mechanism by which CTCF binding sites function as insulator elements was investigated by Prof. Qiang Wu's team at Institute of Systems Biomedicine and Shanghai Jiao Tong University in China and Prof. Bing Ren's team at Ludwig Institute for Cancer Research in the United States. Here we mainly review and discuss some of these latest progresses.