Childhood Cancer Research Articles

Preventing adverse events during paediatric cancer treatment: protocol for a multi-site hybrid randomised controlled trial of catheter lock solutions (the CLOCK trial)

IntroductionCentral venous access devices (CVADs) are commonly used for the treatment of paediatric cancer patients. Catheter locking is a routine intervention that prevents CVAD-associated adverse events, such as infection, occlusion...

Linguistic isolation correlates with length of stay and mortality for pediatric oncology patients in California.

To evaluate social drivers of health and how they impact pediatric oncology patients' clinical outcomes during pediatric intensive care unit (PICU) admission via correlation with patient ZIP codes. Demographic, clinical, and outcome variables from Virtual Pediatric Systems®, LLC for oncology patients (2009-2021) in California PICUs (excluding postoperative) using 3-digit ZIP Codes with social drivers of health variables linguistic isolation, poverty, race/ethnicity, and education abstracted from American Community Survey data for 3-digit ZIP Codes using the Environmental Protection Agency's EJScreen tool. Outcomes of length of stay (LOS), mortality, acuity scores, were compared with social variables. Positive correlation between mortality and minority racial groups (Hispanic/Latino) across ZIP Codes (correlation coefficients of 0.45 (95% CI: 0.22-0.64, p < 0.001) in 2017, 0.50 (95% CI: 0.27-0.68, p < 0.001) in 2018, 0.33 (95% CI: 0.07-0.54, p = 0.013) in 2020, and 0.32 (95% CI: 0.06-0.53, p = 0.018) in 2021). Median PICU length of stay significantly correlated with linguistic isolation (coefficient of 0.42 (95% CI: 0.18-0.61, p = 0.001) in 2021 versus -0.41 (95% CI: -0.61 to -0.16, p = 0.002) in 2019), which included PRISMIII (n = 7417). Mixed effects logistic regression model for other constant variables (PRISMIII, cancer type, race/ethnicity, year), random effect of patient, linguistic isolation (percentage as a continuous value) was significantly associated (95% CI: 1.01-1.06; p = 0.02) with mortality; (OR = 1.03). Linguistic isolation was correlated with LOS and mortality, however variable year to year.

Development and Evaluation of High-Resolution Melting Assays for Direct and Simultaneous Pathogen Identification in Bloodstream Infections in Pediatric Oncology Patients

Blood culture, the gold-standard method for identifying pathogens in bloodstream infections, is time-consuming and demonstrates low sensitivity. These drawbacks are related to high mortality, especially among pediatric oncology patients presenting febrile neutropenia episodes. Here we describe two novel High-Resolution Melting assays designed for pathogen detection in bloodstream infections. The assays were initially evaluated using five sepsis-associated pathogens. Both assays demonstrated 100% specificity, detected as low as 100 fg of bacterial DNA, and exhibited reproducibility. Clinical isolates from blood cultures were 100% identified by both assays. Moreover, blind and direct identification of blood samples from pediatric cancer patients demonstrated sensitivities of 61.5% and 69.2% for “Primer Set 1” and “Primer Set 2”, respectively. Our study highlights the potential of HRM-based assays as a rapid and efficient diagnostic approach for sepsis-related microorganisms. Further advancements could enhance their clinical utility for better management of febrile neutropenia episodes, especially in pediatric oncology patients.

Ewings sarcoma in pediatric population of North India: Demographics, outcome & prognostic factors

BackgroundEwings sarcoma is relatively rare and accounts for a 3–4% of childhood cancer. The data of Ewings sarcoma is scarce in North India and so the study was planned to find out the demographics, outcome and prognostic factors of Ewings sarcoma. MethodsThis is a retrospective study conducted in the Department of Pediatrics, Pediatric Oncology unit at a tertiary care centre (KGMC, Lucknow) in North India. All patients of age 1–16 years with biopsy and IHC proven Ewings sarcoma during 2015–2020 were included in the study. Parameters were noted and follow up was done till December 2021. Statistical analysis was done by Microsoft Excel and GraphPad Prism 10. Overall survival was assessed using Kaplan Meir Survival Analysis. P value < 0.05 was considered significant. Results75 patients i.e.4.1 % of the total were diagnosed with ES. Median age of patients was 10 years. 37.35 % had metastasis at presentation. 32 % were defaulters (abandoned and not taking treatment). Extremity ES constituted 46.7 % of the patient. 29.4 % patients relapsed. The overall survival of the whole cohort was 23.5 % and OS of localised disease was 42.3 %. OS of patients with respect to various sites failed to show any significance. Staging of disease have shown to be affecting outcome. ConclusionProportion of Ewings sarcoma was in accordance with the world's data but the survival outcome was low at our centre primarily due to delayed presentation translating to metastatic disease at diagnosis and abandonment issues along with defaults in treatment. Conducting focussed group discussions, awareness sessions, caregivers counselling and educating them about disease might help in curbing these factors.

Centring children's lived experiences in understanding the importance of play in hospitals.

Children have a right to participate in matters affecting their lives. With increasing regularity, children's perspectives are being sought regarding their health and health care experiences. Though there is evidence that children find play to be one of the 'best' aspects of hospitalisation, studies rarely focus on children's perspectives on play in hospital. This qualitative study explored children's lived experiences of play during hospitalisation. Over five months, ethnographic observations were conducted on a paediatric oncology ward as well as interviews with 16 children ages 3-13 years. Using interpretative phenomenological analysis, children's expressions and experiences illuminated three key points: safety and comfort are integral to children feeling able to play in hospital; the value and efficacy of play is decided by children; and that play is a way for patients to be (and be treated as) children first. Hospitals can only be child-friendly if children find them friendly. Listening to and integrating children's perspectives in the discourse around the importance of play in hospital is essential for respecting children's rights and delivering person-centred paediatric healthcare.

Comparison of two bioelectrical impedance analyzers for estimating body composition in a cohort of pediatric oncology patients

Background and AimsUnfavourable changes in body composition are frequently reported in children with cancer. An easy and affordable method to measure body composition is bioelectrical impedance analysis (BIA). In this study, we compared the Tanita MC780-MA Body Composition Analyzer (Tanita) versus the Bodystat Quadscan 4000 analyzer (Bodystat) to determine whether the Tanita is a suitable analyzer for pediatric oncology patients. MethodsIn this study, 84 childhood cancer patients/survivors were included. Per patient 1, 2 or 3 visits were planned during or after treatment. During each visit, BIA measurements were performed first with the Tanita analyzer followed by the Bodystat analyzer. In total, 131 measurements were included. Spearman correlation and concordance correlation coefficients of Lin (CCC) were calculated for fat percentage (Fat%), fat mass (FM) and fat free mass (FFM). Bland-Altman plots were constructed to assess the agreement between both analyzers. ResultsFat%, FM and FFM values differed statistically significantly when comparing the BIA devices (Wilcoxon signed rank test, p<0.001), but absolute differences between medians were small. Spearman correlations and CCC’s were high for FM (0.94 and 0.92, respectively) and FFM (0.99 and 0.99, respectively), but moderate for Fat% (0.70 and 0.65, respectively). Bland-Altman plots did not show low differences of means (biases; for Fat%, FM and FFM 2,6%, 0,6 kg and -0,6 kg respectively), but relatively large limits of agreement (-9.77% – 15.89% , -5.6 kg – 7.2 kg and -5.9 kg – 4.6 kg respectively). ConclusionsBased on the good agreement between the Tanita and Bodystat on group level, and the fact that the Tanita is a more patient-friendly device, the Tanita can be used to measure body composition instead of the Bodystat in pediatric oncology patients, making it easier and faster to gain information about body composition.

GD2 targeting CAR T cells for neuroblastoma

Treatment of neuroblastoma is a significant clinical unmet need in paediatric oncology epitomised by high-risk disease in which relapse is common and outcomes for children with relapse or primary refractory disease are typically poor, with 4-year progression-free survival for relapse/refractory disease of 6%. Immunotherapy targeting disialoganglioside GD2 using monoclonal antibodies (mAb) has become a component of standard of care treatment in neuroblastoma following published studies that have demonstrated clinical activity and survival benefit associated with this treatment. Hence a number of research groups have developed and clinically evaluated chimeric antigen receptor gene modified T cells (CAR-T cells) targeting GD2 in patients with relapsed and refractory neuroblastoma. Preclinical and clinical results using a range of receptor technologies and immune effectors have demonstrated the basic safety and feasibility of this approach, progressing into clinical data exhibiting promise for sustained patient benefit.

Developmental defects of enamel in childhood cancer survivors: A systematic review and meta-analysis.

The present systematic review and meta-analysis (Prospero registration number: CRD42023472016) aims to assess the prevalence of developmental defects of enamel (DDEs), qualitatively and/or quantitatively, in childhood cancer survivors (CCS) and evaluate, when possible, these data in comparison with those found in healthy children. Three electronic databases (PubMed, Embase, Scopus) were searched from January 2003 to January 2024 for studies reporting on DDEs in children with a mean age not exceeding 16 years at the time of the study who underwent antineoplastic therapy. The ROBINS-I and the Joanna Briggs Institute (JBI) tools were used to assess the risk of bias. Included studies with comparable outcomes underwent random effects models meta-analysis using Stata®18. CCS showed a higher prevalence of DDEs, both qualitative and quantitative, compared to healthy children. The meta- analysis showed higher odds of developing qualitative defects over quantitative defects in CCS. Conclusions regarding the association between the type of therapy administered, age of therapy initiation, and prevalence of DDEs could not be drawn due to insufficient data. A lack of a standardized method of detecting enamel defects posed a challenge in the qualitative and quantitative analysis.

Genetic testing for childhood cancer predisposition syndromes: controversies and recommendations from the SIOPE Host Genome Working Group meeting 2022

Genetic testing for childhood cancer predisposition syndromes: controversies and recommendations from the SIOPE Host Genome Working Group meeting 2022

Alkylating agents-induced gonadotoxicity in prepubertal males: Insights on the clinical and preclinical front.

Rising cure rates in pediatric cancer patients warrants an increased attention toward the long-term consequences of the diagnosis and treatment in survivors. Chemotherapeutic agents can be gonadotoxic, rendering them at risk for infertility post-survival. While semen cryopreservation is an option that can be provided for most (post)pubertal boys before treatment, this is unfortunately not an option prepubertal in age, simply due to the lack of spermatogenesis. Over the last couple of years, studies have thus focused on better understanding the testis niche in response to various chemotherapeutic agents that are commonly administered and their direct and indirect impact on the germ cell populations. These are generally compounds that have a high risk of infertility and have been classified into risk categories in curated fertility guidelines. However, with it comes the lack of evidence and the challenge of using informative models and conditions most reflective of the physiological scenario, in short, the appropriate study designs for clinically relevant outcomes. Besides, the exact mechanism(s) of action for many of these "risk" compounds as well as other agents is unclear. Understanding their behavior and effect on the testis niche will pave the way for incorporating new strategies to ultimately combat infertility. Of the various drug classes, alkylating agents pose the highest risk of gonadotoxicity as per previously established studies as well as risk stratification guidelines. Therefore, this review will summarize the findings in the field of male fertility concerning gonadotoxicity of akylating agents as a result of chemotherapy exposure.

A nine-year-old child with nasopharyngeal cancer treated with concomitant chemoradiotherapy with cisplatin – a case report

In recent years, the role of radiation oncology in treating various pediatric cancers has been extensively researched and developed. The dosage of radiotherapy, when combined with chemotherapy, was either reduced in some oncological diseases or modified in other cancers. Despite these changes, due to swift advancements in radiation oncology technology, this combination therapy continues to enhance both overall and progression-free survival rates, maintaining its vital status as a therapeutic approach in precision medicine. We report here a nine-year-old patient with nasopharyngeal carcinoma treated according to SIOPE guidelines, which included induction neoadjuvant chemotherapy followed by concurrent chemoradiotherapy with cisplatin. Post-therapy imaging assessments revealed a persistent tumor mass with reduced dimensions on MRI one month after treatment, characterized by absence of contrast enhancement, water diffusion restriction, or lymphadenopathy. Subsequent CT imaging at three months post-radiotherapy showed no signs of disease progression. Repeat MRI scans at four and six months post-treatment demonstrated stable disease without evidence of water diffusion restriction, indicating a positive response to therapy. These results underscore the effectiveness of the multimodal approach in achieving favorable tumor control and therapeutic efficacy in pediatric nasopharyngeal carcinoma.

Analysis of Pulmonary Complications in Pediatric Acute Lymphocytic Leukemia Patients following Three Years of Chemotherapy Treatment: A Cross-Sectional Study

Background: This study aimed to investigate the pulmonary side effects of chemotherapy drugs in children with Acute Lymphocytic Leukemia (ALL) three years after treatment. The results could be of great help in managing lung complications in pediatric oncology patients. Materials and Methods: This cross-sectional descriptive study included 50 patients (22 males and 28 females) with ALL. Data were collected from patients' files, including age, sex, duration of illness, last dose of chemotherapy, and medications such as PEG.Asparginas, Cyclophosphamid, thioguanine, Dexamethason, cytarabin, cytosin.arabinosid, vincristine, mercaptopurine, and methotrexate. Pulmonary function tests (Forced Vital Capacity (FVC), FEV1 (Forced Expiratory Volume in the first second)) were assessed by spirometry. Results: Out of 50 patients, 47 (94%) did not have pulmonary disorders, while 3 (6%) had pulmonary dysfunction. Forty-seven patients (94%) did not have respiratory symptoms. FVC results showed that 45 patients were normal, and 5 were abnormal. Similarly, 45 patients had normal FEV1, and 5 had abnormal results. Spirometry results were normal in 45 patients and abnormal in 5. A significant relationship was found between the use of these drugs in different doses and spirometry results, recurrence rate, and pulmonary complications (P &lt;0.05). No significant relationship was observed between pulmonary dysfunction and other drugs (P&gt; 0.05). No correlation was found between pulmonary complications due to chemotherapy with duration of chemotherapy, patient age, and patient gender (P&gt; 0.05). Conclusion: Pulmonary dysfunction and respiratory syndrome were observed in 6% of patients receiving chemotherapy. A significant relationship was found between the frequency of pulmonary and respiratory complications with some chemotherapy drugs in children with ALL. Further research is needed to optimize treatment strategies and minimize lung complications in pediatric oncology patients.

Healthcare Communication Experiences of Hispanic Caregivers of Childhood Cancer Survivors.

Interpersonal communication is a crucial component of the cancer experience that can contribute to managing cancer care and improving cancer survivors' and caregivers' quality of life. Cultural and contextual factors may impact Hispanic childhood cancer survivor (CCS) and parent caregiver relationships and communication. This study sought to describe the healthcare communication experiences of Hispanic parents with CCS, families, and medical providers. We conducted 15 semi-structured interviews with Hispanic caregivers from a safety-net hospital in Los Angeles County. Interviews were conducted in English and Spanish, audio-recorded and professionally transcribed, and analyzed using a thematic approach. Caregivers shared the importance and impact of medical communication when exploring the "first big talk" of the diagnosis, uncertainty about treatment, navigating multiple providers, therapeutic communication (i.e., providing emotional reassurance), and current and lingering effects of cancer. All caregivers shared "good communication" experiences, while others shared various barriers to communication, including a lack of understanding of the cancer diagnosis and caregiver experience, psychological challenges impacting communication, cultural and language differences, physical factors that limit communication, and young age of child impacting communication with caregivers. Our findings suggest that a strong interpersonal communication skill set for clinicians can contribute to managing cancer care and improving caregivers' psychological adjustment.

Using Neurocognitive Phenotypes to Inform Interventions for Adult Survivors of Childhood Cancer.

Neurocognitive impairments are sequelae of childhood cancer treatment, however little guidance is given to clinicians on common phenotypes of impairment, or modifiable risk factors that could lead to personalized interventions in survivorship. Standardized clinical testing of neurocognitive function was conducted in 2,958 (74.1%) eligible survivors, who were ≥5 years post-diagnosis and >18 years old, and 477 community controls. Impairment was examined across 20 measures and phenotypes were determined by latent class analysis. Multinomial logistic regression was used to estimate risk for phenotype, predicted by cancer diagnosis and treatment exposures, chronic health conditions, and lifestyle, adjusted for sex and age. Associations between phenotypes and social attainment were examined. Five neurocognitive phenotypes were identified in survivors (global impairment 3.7%, impaired attention 5.0%, memory impairment 7.2%, processing speed/executive function impairment 9.3%, no impairment 74.8%). Risk of global impairment was associated with severe chronic health condition burden (odds ratio [OR]=20.17, 95% confidence interval [95%CI] 11.41-35.63) including cerebrovascular disease (OR = 14.5, 95%CI = 5.47-38.44) and cerebrovascular accident (OR = 14.7, 95%CI = 7.50-26.40). Modifiable risk factors, like quitting smoking reduced risk for global impairment (OR = 0.21, 95%CI 0.06-0.66). Low physical activity increased risk for global impairment (OR = 4.54, 95%CI 2.86-7.21), attention impairment (OR 2.01, 95%CI 1.41-2.87), processing speed/executive function impairment (OR 1.90, 95%CI 1.46-2.48), and memory impairment (OR 2.09, 95%CI 1.54-2.82). Results support the clinical utility of neurocognitive phenotyping to develop risk profiles and personalized clinical interventions, such as preventing cerebrovascular disease in anthracycline treated survivors by preventing hypercholesterolemia, smoking, and sedentary lifestyle, to reduce the risk for global impairment.

Telomere Length in Adolescent and Young Adult Survivors of Childhood Cancer.

We examined the leukocyte relative telomere length (RTL) in Korean adolescent and young adult (AYA) survivors of childhood cancer and evaluated the association of leukocyte RTL with multiple factors, including malignancy type, cancer treatment, age, and chronic health conditions (CHCs). Eighty-eight AYA survivors of childhood cancer with a median follow-up period of 73 months were recruited. RTL in pediatric cancer survivors was not significantly shorter than the predicted value for age-matched references. Neither age at diagnosis nor duration of therapy influenced the RTL. Among the 43 patients with hematologic malignancies, those who underwent allogeneic hematopoietic stem cell transplantation (HSCT) showed a significant shortening of the RTL compared with those who did not (p = 0.039). Among the 15 patients who underwent allogeneic HSCT, those who developed acute graft-versus-host disease (GVHD) of grade II or higher had significantly shorter RTL than those who did not (p = 0.012). Patients with grade II CHCs had significantly shorter RTL than those without CHCs or with grade I CHCs (p = 0.001). Survivors with ≥2 CHCs also exhibited shorter RTL (p = 0.027). Overall, pediatric cancer survivors had similar telomere lengths compared to age-matched references. HSCT recipients and patients with severe or multiple CHCs had shorter telomeres. GVHD augmented telomere attrition in HSCT recipients.

Bone Marrow-Suppressive Treatment in Children Is Associated with Diminished IFN-γ Response from T Cells upon Polyclonal and Varicella Zoster Virus Peptide Stimulation.

Severe haematological diseases and lymphoid malignancies require bone marrow (BM)-suppressive treatments. Knowledge regarding the impact of BM-suppressive treatments on children's memory T cells is very limited. Memory T cells play a crucial role in defending against herpesviruses, which is particularly relevant in paediatric cancer care. We studied 53 children in total; 34 with cancer and 2 with severe haematological disorders, with some receiving BM-suppressive treatment with or without allogeneic-haematopoietic stem cell transplantation (allo-HSCT), alongside 17 healthy controls. We focused on peripheral blood proportions of memory T-cell subsets using flow cytometry and analysed cytokine-secreting T cells with a four-parameter FluoroSpot assay in response to T-cell mitogen and varicella zoster virus (VZV) peptides. Patients on BM-suppressive treatment showed increased clusters of differentiation (CD)4+ and CD8+ effector memory (TEM)/terminally differentiated effector (TEFF) T cells compared to the healthy controls. They also exhibited, amongst other things, when compared to the healthy controls, a reduced total number of cytokine-secreting cells, by means of interferon (IFN)-γ, interleukin (IL)-17A, IL-10, and IL-22, following mitogen activation. A diminished IFN-γ response among the children with BM-suppressive treatment was observed upon VZV-peptide stimulation, compared to the healthy children. Collectively, the findings herein indicate that the children who are undergoing or have finished BM-suppressive treatment display qualitative differences in their T-cell memory compartment, potentially increasing their susceptibility to severe viral infections and impacting their immunotherapy, which relies on the functional ability of autologous T cells.

Synthesis and Antitumour Evaluation of Tricyclic Indole‐2‐Carboxamides against Paediatric Brain Cancer Cells

Antitumour properties of some cannabinoids (CB) have been reported in the literature as early as 1970s, however there is no clear consensus to date on the exact mechanisms leading to cancer cell death. The indole‐based WIN 55,212‐2 and SDB‐001 are both known as potent agonists at both CB1 and CB2 receptors, yet we demonstrate herein that only the former can exert in vitro antitumour effects when tested against a paediatric brain cancer cell line KNS42. In this report, we describe the synthesis of novel 3,4‐fused tricyclic indoles and evaluate their functional potencies at both cannabinoid receptors, as well as their abilities to inhibit the growth or proliferation of KNS42 cells. Compared to our previously reported indole‐2‐carboxamides, these 3,4‐fused tricyclic indoles had either completely lost activities, or, showed moderate‐to‐weak antagonism at both CB1 and CB2 receptors. Compound 23 displayed the most potent antitumour properties among the series. Our results further support the involvement of non‐CB pathways for the observed antitumour activities of amidoalkylindole‐based cannabinoids, in line with our previous findings. Transcriptomic analysis comparing cells treated or non‐treated with compound 23 suggested the observed antitumour effects of 23 are likely to result mainly from disruption of the FOXM1‐regulated cell cycle pathways.

Inhibition of Histone Deacetylase Activity Increases Cisplatin Efficacy to Eliminate Metastatic Cells in Pediatric Liver Cancers.

New cell lines were generated from primary hepatoblastoma liver tumors (hbl) and lung metastases (LM) of HBL patients. In addition, cell lines were generated from hepatocellular neoplasm, not otherwise specified (HCN-NOS) tumor samples, and hcc cell lines. Hbl, LM and hcc cells were treated with cisplatin, SAHA or in combination. The effect of these drugs on the number of cells, formation of tumor clusters and HDAC1-Sp5-p21 axis were examined. Both HBL and HCC tissue specimens have increased HDAC1-Sp5 pathway activation, recapitulated in cell lines generated from the tumors. HDAC inhibition with vorinostat (SAHA) increases cisplatin efficacy to eliminate CAFs in hbl and in hcc cell lines. Although the neuron-like cells survive the combined treatments, proliferation was inhibited. Notably, combining SAHA with cisplatin overcame cisplatin resistance in an LM cell line from an aggressive case with multiple metastases. Underlying mechanisms of this enhanced inhibition include suppression of the HDAC1-Sp5 pathway and elevation of an inhibitor of proliferation p21. Similar findings were found with gemcitabine treatments suggesting that elimination of proliferative CAFs cells is a key event in the inhibition of mitotic microenvironment. Our studies demonstrate the synergistic benefits of HDAC inhibition and cisplatin to eliminate metastasis-initiating cells in pediatric liver cancers.

The impact of clinically relevant health conditions on psychosocial outcomes in survivors of childhood cancer: results of the DCCSS-LATER study.

Investigate the association between presence, number and type of clinically relevant health conditions and a range of psychosocial outcomes (emotional, social, cognitive, physical) in survivors of childhood cancer (CCS). CCS from the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER cohort (diagnosed between 1963-2001, attained age ≥ 18, diagnosed < 18, ≥ 5years since diagnosis) completed a questionnaire on health conditions (2013-2014), and questionnaires on psychosocial outcomes (2017-2020): Hospital Anxiety and Depression Scale, Short form 36, TNO-AZL Questionnaire for Adult Health-Related Quality of Life, and the Self-Rating Scale for Post-Traumatic Stress Disorder. Associations among health conditions and psychosocial outcomes were assessed with regression analysis, adjusting for attained age, sex, and time since diagnosis, and adjusting for multiple testing (p < 0.004). A total of 1437 CCS, mean age 36.3years, 51.1% female, ≥ 15years since diagnosis, completed questionnaires on health and psychosocial outcomes. CCS with a clinically relevant health condition, and those with more conditions had worse emotional, social, and physical outcomes; regression coefficients were small to moderate. CCS with gastro-intestinal conditions, endocrine, nervous systems, eye, or ear conditions, and especially those with secondary malignant neoplasms, reported worse psychosocial functioning; regression coefficients were small/moderate to large. Health care professionals should be aware of the increased risk for psychosocial problems among CCS with health conditions, especially for survivors with secondary malignant neoplasms, gastro-intestinal, endocrine, nervous system, eye, and ear conditions. CCS may benefit from psychological interventions to develop coping strategies to manage health conditions and psychosocial consequences of the cancer trajectory.

Characterization of transcriptional heterogeneity and novel therapeutic targets using single cell RNA-sequencing of primary and circulating Ewing sarcoma cells.

Ewing sarcoma is the second most common bone cancer in children, accounting for 2% of pediatric cancer diagnoses. Patients who present with metastatic disease at the time of diagnosis have a dismal prognosis, compared to the >70% 5-year survival of those with localized disease. Here, we utilized single cell RNA-sequencing to characterize the transcriptional landscape of primary Ewing sarcoma tumors and surrounding tumor microenvironment (TME). Copy-number analysis identified subclonal evolution within patients prior to treatment. Primary tumor samples demonstrate a heterogenous transcriptional landscape with several conserved gene expression programs, including those composed of genes related to proliferation and EWS targets. Single cell RNA-sequencing and immunofluorescence of circulating tumor cells at the time of diagnosis identified TSPAN8 as a novel therapeutic target.