Childhood Malignancies Research Articles

MEDB-55. Single-cell transcriptomics reveals progenitor cells expressing a photoreceptor program as putative cells origin of MYC-driven Group 3 Medulloblastoma

Brain tumors are the leading cause of childhood cancer-related death. Medulloblastoma is the most common malignant pediatric brain tumor with about 70% survival. Medulloblastoma comprises four distinct subgroups respective of genomic and molecular drivers influencing tumorigenesis. It has been established that despite being considered a single disease entity, each subgroup arises from a distinct population of cells found within unique compartments of the developing brain. The cell of origin of Group 3 medulloblastoma, the most malignant medulloblastoma subgroups, is currently unknown and remains controversial. Transcriptional profiling has revealed that Group 3 medulloblastomas are characterized by elevated expression of a photoreceptor program, which has not been described in the normal cerebellar development but is well characterized in the developing pineal gland and retinal. By investigating and comparing brain and tumor development between our previously developed medulloblastoma mice model (GMYC), where mice spontaneously develop Group 3 medulloblastoma after 4-6 months of age, and their control counterparts, we found that tumor cells emerged from progenitor cells where MYC overexpression drove the transformation of immature progenitor cells expressing a photoreceptor program. Our data suggest that MYC-driven Group 3 medulloblastoma originates from progenitor cells expressing a photoreceptor program, which has implications for future research and the development of novel treatments targeting this devastating childhood malignancy.

OTHR-30. Multidisciplinary approach to childhood cancer bio-banking improves enrollment and enables better access to diagnostic and therapeutic studies

Abstract Despite the significant progress made in the multi-modal treatment of childhood malignancies over the last four decades with a concomitantly increased cure rates, the benefit is still largely limited to patients with leukemias, lymphomas and localized non-CNS solid tumors, leaving patients with high-risk non-CNS solid tumours and most CNS malignancies with minimal advancements. More research is critical to understand what drives these cancers and to investigate the best ways to deliver curative therapies. Translational research relies on patient-derived tissue samples, animal models and cell-cultures to understand the biological, genetic, and molecular mechanisms of disease. To facilitate patient care and outcomes, it is becoming increasingly important that paediatric clinical trials include tissue availability as part of eligibility criteria, making collection and storage of patient tissue a mandate of personalised medicine and a pillar of modern paediatric cancer medicine. Monash Children’s Cancer Biobank was established in 2011. Since 2017, a total of 64 patients were diagnosed with CNS malignancies across all grades, with an overall 69% of patients’ tissues being biobanked at the time of initial diagnosis. A co-ordinated, multidisciplinary approach to biobanking is crucial to the success of tissue acquisition. Through the combination of an educational forum, regular neuro-surgical multi-disciplinary meetings, and the early involvement of medical oncology and biobank staff, with our neurosurgical and clinical pathology colleagues, as part of patient management planning, the tissue acquisition for biobanking increased from 44% to 82% over the course of 5 years. This consequently led to a 100% enrolment to tissue-enabling studies, significantly improving identification of targetable molecular lesions, enrolment onto treatment clinical trials and identification of patients with cancer predisposition syndromes.

MEDB-09. Unraveling the role of unfolded protein response in medulloblastoma cancer stem cells

Medulloblastoma (MB) is the most common malignant childhood brain tumor. The current clinical approach consists of multimodal strategies with debilitating long-term effects and risk of tumor recurrence. Medulloblastoma stem cells (MBSCs) are a fraction of tumor cells with high proliferation potential and the capability to adapt to adverse/restrictive conditions in tumor milieu thus driving the refractoriness to conventional therapies. Recently, high basal levels of Unfolded Protein Response (UPR) molecules have been found in tumors of different tissue-origin and are correlated with poor prognosis and low patient survival. However, little is known about the role of UPR in MB. We investigated the expression and activation of UPR players in MBSCs. Human group 3 MB (G3MB) cell lines, specifically CHLA-01, D283- and D341-Med, were grown in Vitamin A and/or FBS or in stem selective medium (B27™) for 72 h before collection. Cells were fixed, stained with proper primary antibodies and images were acquired by confocal microscopy. The analysis of the transcription factors ATF-4 and CHOP revealed their elevated nuclear expression and co-localization, which resulted to be more marked in G3MB stem-like cells than in the differentiated ones. Also the ATF-6 branch was investigated, in differentiating conditions D283 and D341-Med showed a greater activation of ATF-6, represented by its nuclear localization, in respect to stem cells, while CHLA-01 did not show differences. Conversely XBP1, the transcription factor downstream IRE1 signaling, was not expressed in the three cell lines. Lastly, a Kaplan-Meier analysis on MB patients showed a worse prognosis with a shorter survival rate of patients expressing high ATF4 transcript levels. Our results reveal, even in resting conditions, preferential activation of the PERK branch in G3MB cells grown in stem-like condition suggesting that ATF-4 might be a promising therapeutic and prognostic factor to specifically target the stem compartment in aggressive MB.

MEDB-45. Functional genomics identifies epigenetic regulators as novel therapeutic targets for sonic hedgehog medulloblastoma

Medulloblastoma (MB) is among the most common malignant childhood brain tumors that comprises a group of four molecularly distinct diseases. A significant proportion of these tumors is characterized by aberrant activation of the canonical sonic hedgehog (SHH) signaling pathway. Although small-molecule inhibitors targeting Smoothened (SMO) have proven a promising treatment approach for SHH-MB subgroup, primary or acquired resistance impedes its clinical efficacy. Therefore, novel targeted approaches are urgently needed to improve therapeutic strategies for this tumor entity. Here, we conducted a genome-wide CRISPR/Cas9 knockout screen in a murine and a human SHH-MB cell line, SMB21 and DAOY, respectively, in order to decipher tumor-specific genetic dependencies. Our data demonstrate that SMB21 cells highly depend on positive regulators of the SHH pathway, such as Smo and Gli1 for their survival, as opposed to DAOY cells, suggesting that the latter does not represent a faithful model of SHH-MB. Members of the epigenetic machinery such as Dnmt1 and Smarca5 scored strongly as SMB21-context specific essentialities. Pharmacologically, we show that DNMT1 inhibition is efficacious at clinically relevant concentrations against SMO inhibitor- sensitive, as well as resistant SHH-MB cell lines, indicating novel therapeutic avenues for SHH-MB. By performing RNA sequencing of SMB21 cells, we identified early and late changes in global gene expression induced by DNMT1 inhibition, including decreased expression of mediators of SHH signaling, such as Gli1 and Gli2. Of note, gene set enrichment analysis revealed that DNMT1 inhibition downregulates top gene sets associated with cell cycle progression, corroborating the screening results that Dnmt1 is essential for SMB21 proliferation. Further global DNA methylation profiling in SMB cells will help to define the molecular basis of sensitivity to DNMT1 inhibitors in SHH-MB. Summarizing, our data highlight the potential of inhibitors targeting epigenetic regulators in SMO inhibitor- sensitive and resistant MB for more efficacious treatment options.

MEDB-77. Metastasic medulloblastoma: radiological features and its correlation with molecular subgroups and dissemination pattern

Medulloblastoma (MB) is the most frequent malignant childhood brain tumor. Four molecular subgroups have been described (WNT, SHH, group3, group4), which are associated with a different biological profile, prognosis, specific MRI characteristics and patterns of metastatic dissemination. We aimed to determine the imaging features of the metastatic MB and its molecular subgroup and their outcomes. Retrospective single-center analytic-observational study conducted from January 2004-January 2022 in a tertiary-care center. Pediatric patients with metastatic medulloblastoma at disease onset were included. We collected epidemiological and clinical characteristics, treatment received, and outcomes. The molecular subgroup was determined by its methylation profile. MRI were reviewed by the neuroradiologist. Sixty-three patients were diagnosed, 17 (26.9%) were metastatic. The median age at diagnosis was 5.1 years (range 2.1-17.5 years), 58.8% were male. According to histopathologic classification, fifteen patients (93.8%) were classic,1 (6.3%) desmoplastic. Molecular subgroup analysis showed 2 WNT (12.5%), 1 SHH (6.3%), 3 (18.8%) group 3 (G3) and 5 (31.2%) group 4 (G4). Four patients (25%) were classified as G3/G4 and 1 (6.3%) as mixed. Five patients (29.4%) were M2 and 12 patients (70.6%) were M3 according to Chang staging system. The location in the cerebellar hemispheres was only observed in SHH patient while G3 tumors presented homogeneous contrast enhancement. All WNT, G3 and G4 were located in IV ventricle. We found no association between molecular subgroup and metastatic site (intracranial vs spinal, Fisher test, p=0.45). All patients presented with metastasis in the third ventricular infundibular recess were G4. Four patients died, all of them were G3 or G3/G4. Our results supported the literature previously reported. According to the MRI imaging features, the molecular medulloblastoma subgroups could be suggested. The presence of metastasis in the infundibular recess suggested MB group 4. However, the dissemination pattern could not be associated with any subgroup in our series.

E2F3 gene expression is a potential negative prognostic marker for localised and MYCN not-amplified neuroblastoma: Results of in silico analysis of 786 samples.

Neuroblastoma (NB) is an enigmatic childhood malignancy characterised by a wide range of clinical behaviour. Many potential oncogenes for NB have recently been identified. Among them, E2 transcription factor 3 (E2F3) expression was associated with a poor survival in 134 stage 4S patients, but evidence for other stage groups remains poorly investigated. We have analysed the expression of E2F3 gene from a database of 786 NB samples. Overall and event-free survivals (EFS) were assessed by the Kaplan-Meier method, splitting the data on the median and tertile expression values. The Cox model was applied to control for the confounding by stage, age and MYCN amplification. Validation was performed by an in silico analysis of an independent cohort of 283 NB patients. Furthermore, an immunofluorescence analysis on 48 formalin-fixed, paraffin-embedded NB specimens was also performed. E2F3 overexpression was associated with a poor survival (EFS=84%, 95% CI: 79%-95%, for low expression levels; EFS=62%, 95% CI: 56%-68% for middle levels; EFS=30%, 95% CI: 24%-36%, for high levels, p<.001). This association was confirmed in multivariable analysis and was more evident in patients with MYCN not-amplified and localised stages. Immunofluorescence results and the validation on an independent cohort of NB primary samples confirmed these findings. E2F3 is a new potential prognostic marker in NB with favourable characteristics at diagnosis. Further studies are needed to elucidate the potential role of E2F3 in NB oncogenesis and progression, in order to identify new targets for therapeutic interventions.

Multiomics analysis of pediatric solid tumors within the INFORM precision oncology study: From functional drug profiling to biomarker identification.

10036 Background: Within the INFORM (INdividualized Therapy FOr Relapsed Malignancies in Childhood) registry over 1200 childhood malignancies were molecularly profiled using next generation sequencing to identify therapeutic targets. Nevertheless, high evidence targets were only detected in 5% of cases and only 50% of the patients were identified with druggable pathways, while the remaining cases lacked druggable alterations. Thus, an ex-vivo functional drug response profiling platform for pediatric solid tumors has been established within the INFORM program to identify novel biomarkers and unravel molecular mechanisms associated with drug response profiles for clinical translation. Methods: Solid tumors from 97 paediatric patients were screened against a library of 76 drugs. A quality control classification decision tree was designed to select the samples for further analysis. Whole exome sequencing, low-coverage whole genome sequencing, and RNA-seq were used to analyze the molecular profiles of the samples. Molecular features were filtered to retain oncogenic and druggable events. Five data feature views (mutations, mRNA, gene fusions, CNVs, and drug responses) were used to train a Multi-Omics Factor Analysis (MOFA) model to identify prominent latent factors. Results: 81 samples passed the quality control inclusion criteria of which 76 samples had available omics data profiles. Quantitative drug profiling measurements were reported using the selective asymmetric drug sensitivity score.The multi-omics analysis captured five entity-specific omics signatures of Ewing sarcoma, Wilms tumor, BCOR sarcoma, neuroblastoma and ependymoma. Moreover, the analysis revealed sensitivity to navitoclax in neuroblastoma samples with PHOX2B-GATA3 overexpression, and an association between MEK inhibitor sensitivity and an expression signature in Wilms tumors. Conclusions: The combination of functional drug and multi-omics profiling enabled the identification of novel biomarkers for drug sensitivities in pediatric solid tumors. As we continue to expand the number of patient samples evaluated with our drug sensitivity platform, this dataset will provide insights for novel drug targets, and could unravel key molecular events and mechanisms acting towards personalized therapies.

Somatic structural variations in pediatric brain tumors.

Pediatrics brain tumors are the second most frequent malignancy in children, and the most common cause of cancer-related deaths in both the 0-14-year and the 15-24-year age group. Although, pediatrics high-grade glioma (pHGG) is a histologically similar tumor to that arising in adults, these are distinct biological diseases, differing in copy number profiles and driver genetic alterations. Recent sequencing initiatives have conclusively shown the existence of subgroups of HGG marked by distinct driver mutations, which are significantly enriched in young children (H3F3A K27M), teenagers and young adults (H3F3A G34R/V), and middle- aged adults (IDH1/2). Structural rearrangements resulting in novel fusion genes are strongly associated with cancer, and numerous examples exist in both adult and childhood malignancies. Although, only few have been described in pHGG. Structural variants (SV) frequently result in chimeric proteins targetable by novel therapeutic approaches, an outcome desperately needed in pHGG.

A phase 1/2 dose-escalation and dose-expansion study of ZN-c3 in combination with gemcitabine in adult and pediatric subjects with relapsed or refractory osteosarcoma.

TPS11584 Background: Osteosarcoma (OS) is the most common primary bone malignancy of childhood and adolescence with 5-year survival rates of 65-70% for localized disease and &lt; 30% for de novo metastatic disease or recurrent disease. Pooled analysis of previous phase 2 trials by the Children’s Oncology Group has determined a 4-month event-free survival (EFS) of 12%. The Wee1 kinase helps regulate DNA damage repair at the G2-M checkpoint. In the presence of DNA damage, the Wee1 kinase is activated, arresting cells in the G2 phase and preventing entry into the M phase. Inhibition of the Wee1 kinase abrogates the G2-M checkpoint, forcing cancer cells to undergo unscheduled mitosis even in the presence of DNA damage, leading to mitotic catastrophe. However, the Wee1 kinase is often upregulated in OS, preserving the G2-M checkpoint and allowing tumor growth and metastases. Additionally, up to 90% of OS tumors have alterations in p53, a critical protein in the regulation of the G1-S checkpoint, especially in relapsed or refractory cases. With a dysfunctional G1-S checkpoint, cancer cells further rely on G2-M checkpoint to repair DNA damage and preserve genomic integrity. Prior studies have demonstrated that pharmacologic inhibition of the Wee1 kinase produced cell death in OS cell lines and patient-derived xenografts. While p53 mutational status appeared to modulate efficacy of the Wee1 kinase inhibitor, activity was observed in p53 wild type, mutant and null cell lines. Combination therapy studies have also been performed, demonstrating potential synergism with gemcitabine. As expected, by precipitating DNA damage, susceptibility to inhibition of the G2-M checkpoint is further increased. Methods: NCT04833582 is an ongoing, open label, multicenter, phase 1/2 clinical trial to evaluate the activity of ZN-c3, an oral Wee1 inhibitor, in combination with gemcitabine in subjects ≥12 years and ≥40 kg, with relapsed, refractory OS. Subjects are dosed once daily, continuously with ZN-c3 and receive gemcitabine 1000 mg/m2 on days 1 and 8 of 21-day cycles. Up to 18 subjects are expected to enroll in the phase 1 portion based on a typical 3 + 3 escalation design; ̃60 subjects will be enrolled in the phase 2 portion, consisting of three stages: futility, promising clinical activity, and improved precision for clinical activity. The first two stages follow a Simon two-stage optimal design with 30 subjects, to differentiate an EFS rate at 18 weeks between 12% and 36% (which may be considered a more suitable endpoint for OS, compared with radiographic response). Tumor and skin punch biopsies are incorporated into the trial to identify potential biomarkers of treatment response. Subjects must be able to swallow oral tablets and have measurable disease by RECIST v1.1; prior exposure to gemcitabine is allowed. Global enrollment began August 1, 2021, and is ongoing. Clinical trial information: NCT04833582.

Efficacy and safety of outpatient based therapy in childhood acute lymphoblastic leukemia.

e22001 Background: Acute lymphoblastic leukemia (ALL) is the most common malignancy of childhood. With the improvements in effective antileukemic drugs and the risk stratification treatment approach, the cure rate for pediatric ALL has increased to &gt;90%. The effect of outpatient treatment and developing supportive care have a very important role in this success. We evaluated the disease outcomes and severe complications (complication causes hospitalization in ICU, encephalitis) of children who had been treated with the Children’s Oncology Group (COG) protocols, and follow-up protocol during a 20-year study period. Methods: From 1999 to 2020, 134 patients who had been diagnosed with ALL in the Department of Pediatric Hematology-Oncology at the Istanbul University Oncology Institute were included in the present study. Nine patients excluded from all analysis that 5 of them admitted with relapse, 2 had been diagnosed with mature aggressive B-cell acute leukemia, and 2 had been diagnosed with mixed phenotype and 7 who had been lost to follow-up were also excluded from survival analyses. Results: Mean age was 7.7±4.89 years old in 125 patients (Table). The 5- and 10-year and 20-year Event Free Survival (EFS) rates were 90.2% (standard error [SE], 4.2%) in standart risk B-ALL (n=54) and Overall Survival (OS) rates were 100%, 96% and 96% ([SE], 3.9%), respectively. In high risk group B-ALL (n=53) 5-year EFS was 80.7% (standard error [SE], 5.8%) and 78.2% ([SE], 6.1%) for both 10 and 20 year period and OS rates were 76.9% ([SE], 5.9%) for all periods. Although the number of patients is low in T-ALL (n=11), 5- and 10-year and 20-year EFS and OS rates were 63.6% (standard error [SE], 14.5%) for all periods. Fifteen severe complication recorded in 12 patients (10 B-ALL, 2 T-ALL). One patient hospitalized in ICU due to gram negative sepsis for 3-times and epidural hemorrhage. Conclusions: The survival rate for pediatric ALL has increased in recent years according to improvements of treatment.In our cohort, 20-year OS rate is 96% for standart risk B-ALL and 76.9% for high risk B-ALL. Additionally, regularly and closely monitored patients, complications can be effectively prevented, treated, and eliminated. In our study, the short hospitalization period, rapid analysis of laboratory tests, continuous supportive care, efficient education given to the parents of children increased the success of the therapy and ensured low complication rates. [Table: see text]

Multimodal imaging and photothermal synergistic immunotherapy of retinoblastoma with tuftsin-loaded carbonized MOF nanoparticles

Retinoblastoma (Rb) represents 3% of all childhood malignancies and seriously endangers children's lives and quality of life. Early diagnosis and treatment can save children's vision as much as possible. Multifunctional nanoparticles have become a research hotspot in recent years and are expected to realize the integration of early diagnosis and early treatment. Therefore, we report a nanoparticle with dual-mode imaging, photothermal therapy, and immune activation: carbonized MOF nanoparticles (CM NPs) loaded with the immune polypeptide tuftsin (CMT NPs). The dual-mode imaging ability, antitumor effect, and macrophage immunity activation ability of these nanoparticles combined with laser irradiation were studied. The biosafety of CMT NPs was detected. The multifunctional magnetic nanoparticles enhanced photoacoustic (PA) and magnetic resonance (MR) imaging in vivo and in vitro, facilitating diagnosis and efficacy evaluation. The combined effect of CMT NPs and laser irradiation was recorded and verified. Through the accumulation of magnetic field nanoparticles in tumors, the photothermal conversion of nanoparticles under laser irradiation led directly to tumor apoptosis/necrosis, and the release of tuftsin induced macrophage M1-type activation, resulting in antitumor immune effects. Enhanced PA/MR imaging CMT NPs have great potential in dual-mode image-guided laser/immune cotherapy. The nanoparticles have high biosafety and have potential in cancer treatment.

Spatiotemporal multiomic landscape of human medulloblastoma at single cell resolution.

2069 Background: Medulloblastoma is the most common malignant childhood tumor type with distinct molecular subgroups. While advances in the comprehensive treatment have been made, the mortality in the high-risk group is still very high, driven by an incomplete understanding of cellular diversity. Methods: We use single-nucleus RNA expression, chromatin accessibility and spatial transcriptomic profiling to generate an integrative multi-omic map in 40 human medulloblastomas spanning all molecular subgroups and human postnatal cerebella, which is supplemented by the bulk whole genome and RNA sequences across 300 cases. Results: This approach provides spatially resolved insights into the medulloblastoma and cerebellum transcriptome and epigenome with identification of distinct cell-type in the tumor microenvironment. Medulloblastoma exhibited three tumor subpopulations including the quiescent, the differentiated, and a stem-like (proliferating) population unique to cancer, which localized to an immunosuppressive-vascular niche. We identified and validated mechanisms of stem-like to differentiated process among the malignant cells that drive tumor progression. Integration of single-cell and spatial data mapped ligand-receptor networks to specific cell types, revealing stem-like malignant cells as a hub for intercellular communication. Multiple features of potential immunosuppression and angiogenesis were observed, including Treg cells and endothelial cells co-localization in compartmentalized tumor stroma. Conclusions: Our study provides an integrative molecular landscape of human medulloblastoma and represents a reference to advance mechanistic and therapeutic studies of pediatric neuro-oncological disease.

Prevalence of micronutrient deficiency and its impact on the outcome of childhood cancer: A prospective cohort study

Impact of micronutrient deficiency on childhood malignancy is unexplored. We estimated the prevalence of baseline micronutrient deficiency in children with cancer and its impact on event-free survival (EFS) and overall survival (OS). A longitudinal cohort study was conducted at a tertiary cancer centre in India. Children (≤18 years) with de novo malignancy were enrolled between October 2012 and May 2014. Baseline levels of vitamin B12, folate, zinc, selenium, copper, and iron were measured and values below 150pmol/L, 6ng/mL, International Zinc Nutrition Collaborative Group cut-off, 0.5μmol/L, 10μmol/L, and 50μg/dL, respectively, indicated deficiency. Total 535 children [326 (60.9%) haematological and 209 (39.1%) solid malignancies] were enrolled with median follow-up of 66 months. Vitamin B12, folate, zinc, selenium, copper and iron deficiencies were found in 209 (39.1%), 89 (16.6%), 173 (32.3%), 39 (7.3%), 12 (2.2%), and 231 (43.2%) children, respectively. Selenium deficiency independently predicted poor EFS (hazard ratio [HR]=1.56; p=0.038) and OS (HR=1.65; p=0.027) in the cohort. In haematological malignancies, selenium deficiency predicted poor EFS (HR=1.81; p=0.023) and OS (HR=2.12; p=0.004). In solid malignancies, vitamin B12 (HR=1.55; p=0.028) and zinc (HR=1.74; p=0.009) deficiencies predicted poor EFS, and zinc deficiency predicted poor OS (HR=1.77; p=0.009). Multiple micronutrient (≥3) deficiencies also predicted poor EFS (HR=1.69; p=0.001) and OS (HR=1.83; p<0.001) in the whole cohort. Selenium deficiency was independently predictive of adverse outcomes in childhood cancer, particularly in haematological malignancies. Zinc deficiency adversely affected solid tumours. The adjunct use of micronutrient supplementation in paediatric malignancies should be explored.

Environmental cues from neural crest derivatives act as metastatic triggers in an embryonic neuroblastoma model

Embryonic malignant transformation is concomitant to organogenesis, often affecting multipotent and migratory progenitors. While lineage relationships between malignant cells and their physiological counterparts are extensively investigated, the contribution of exogenous embryonic signals is not fully known. Neuroblastoma (NB) is a childhood malignancy of the peripheral nervous system arising from the embryonic trunk neural crest (NC) and characterized by heterogeneous and interconvertible tumor cell identities. Here, using experimental models mimicking the embryonic context coupled to proteomic and transcriptomic analyses, we show that signals released by embryonic sympathetic ganglia, including Olfactomedin-1, induce NB cells to shift from a noradrenergic to mesenchymal identity, and to activate a gene program promoting NB metastatic onset and dissemination. From this gene program, we extract a core signature specifically shared by metastatic cancers with NC origin. This reveals non-cell autonomous embryonic contributions regulating the plasticity of NB identities and setting pro-dissemination gene programs common to NC-derived cancers.

Histopathological patterns of childhood malignancies seen at Federal Teaching Hospital Abakaliki, Ebonyi State, Nigeria: A 10 year retrospective study

Introduction: Childhood malignancies (CM) have been one of the major causes of death in the world. It appears to be increasing in significance due to the ongoing reduction in both infectious and nutritional diseases.Aims: The study was conducted to document the histopathological pattern, age and sex distribution of childhood malignancies in a University Teaching Hospital in Southeast Nigeria.Method: The materials consisted of histology slides, formalin-fixed paraffin-embedded tissue blocks (FPTB), and requisition forms of all cases diagnosed with CM at a University Teaching Hospital between the periods January 2005 and December 2015Results: A total of 2,528 surgical biopsies were received at the Department. Only 60 (2.4%) specimens represented childhood malignancies. Thirty-one cases (51.7%) of the entire CM were lymphomas; 12 (20.0%) were non-Hodgkin lymphoma, 17 (28.3%) others were Burkitt’s type whereas 2(3.3%) were Hodgkin lymphoma. Childhood malignancies were more in males 36 (60.0 %) than females 24 (40.0%), giving a male to female ratio of 3:2. However, Burkitt’s lymphoma was higher in females 12 (70.6%) than males 5 (29.4%) with a male to female ratio of 1.2:3. Twenty-six (43.3%) cases of the CM occurred in children aged 0-5 years but 20 (36.7%) presented in children aged 11 to 15 years. Twelve (20.0%) cases were seen in children 6 to 10 years. Six (23.1%) of the children had Burkitt's lymphoma all of whom were under 5 years.Conclusion: Lymphomas were the commonest CM, Burkitt’s lymphoma being the dominant subtype in this study. There was a female preponderance of Burkitt’s lymphoma.

Perioperative Management of Pediatric Brain Tumors: A Retrospective Analysis.

Brain tumors are the second most common malignancy in childhood and the surgical excision remains the cornerstone of management. The objective of this study was to analyze the factors associated with the length of intensive care unit (ICU) and hospital stay, and postoperative outcome in such children. Three years of data were collected, retrospectively, by detailed review of medical records pertaining to pre-anesthetic evaluation and perioperative course of children less than 16 years of age who underwent excision of intracranial tumors. One hundred sixty-eight medical records were analyzed. One third of the children were found to have developed various intraoperative adverse events; the most common were hemodynamic changes following brainstem handling and brain swelling. 58% of children required postoperative mechanical ventilation. 82.7% of patients had favorable neurologic outcome which was comparable between the two tumor locations (supratentorial vs infratentorial). On multivariate analysis, re-exploration surgery and electrolyte disturbances, such as serum sodium, were found to be the independent risk factors affecting hospital stay. The amount of intraoperative blood loss and postoperative pulmonary complications (POPCs) were independent risk factors affecting the neurologic outcome. Adverse events are fairly common after excision of brain tumors in children. Intraoperative complications did not affect the ICU stay or neurological outcome; however, the postoperative complications increased length of ICU and hospital stays. POPC was the single most important factor responsible for poor neurologic outcome and was more so in children who underwent infratentorial surgery, prolonged mechanical ventilation, and who had a lower cranial nerve palsy.

Single-cell characterization of malignant phenotypes and microenvironment alteration in retinoblastoma.

Retinoblastoma (RB) is the most common primary intraocular malignancy of childhood. It is known that the tumor microenvironment (TME) regulates tumorigenesis and metastasis. However, how the malignant progression in RB is determined by the heterogeneity of tumor cells and TME remains uncharacterized. Here, we conducted integrative single-cell transcriptome and whole-exome sequencing analysis of RB patients with detailed pathological and clinical measurements. By single-cell transcriptomic sequencing, we profiled around 70,000 cells from tumor samples of seven RB patients. We identified that the major cell types in RB were cone precursor-like (CP-like) and MKI67+ cone precursor (MKI67+ CP) cells. By integrating copy number variation (CNV) analysis, we found that RB samples had large clonal heterogeneity, where the malignant MKI67+ CP cells had significantly larger copy number changes. Enrichment analysis revealed that the conversion of CP-like to MKI67+ CP resulted in the loss of photoreceptor function and increased cell proliferation ability. The TME in RB was composed of tumor-associated macrophages (TAMs), astrocyte-like, and cancer-associated fibroblasts (CAFs). Particularly, during the invasion process, TAMs created an immunosuppressive environment, in which the proportion of TAMs decreased, M1-type macrophage was lost, and the TAMs-related immune functions were depressed. Finally, we identified that TAMs regulated tumor cells through GRN and MIF signaling pathways, while TAMs self-regulated through inhibition of CCL and GALECTIN signaling pathways during the invasion process. Altogether, our study creates a detailed transcriptomic map of RB with single-cell characterization of malignant phenotypes and provides novel molecular insights into the occurrence and progression of RB.

Nanoscale Coordination Polymer Based on Bacterial Derivatives for Enhanced Radiotherapy in Neuroblastoma

Neuroblastoma (NB) is one of the most common extracranial malignancies in children, accounting for 7–8% of childhood malignancies. As one of the main treatments for NB, radiotherapy is limited by various factors in clinics, such as the hypoxia microenvironment in tumor and serious side effects. Herein, we synthesized a kind of nanoscale coordination polymer denoted as Hf@DAP nanoparticles composed of hafnium ion (Hf[Formula: see text] and 2,6-diaminopimelic acid (DAP), one of bacterial derivatives. From the image of transmission electron microscope (TEM), nanoparticles had uniform dispersion. Furthermore, the hydrodynamic diameter measured by dynamic light scattering method was about 190 nm. In this structure, the Hf[Formula: see text] can enhance radiotherapy by effectively enhancing the function of X-ray, and the DAP was a biocompatible ligand for fabricating the nanoscale coordination nanoparticles. Furthermore, Hf@DAP nanoparticles were stable in various mediums and exhibited favorable biocompatibility in various cell lines in vitro. Cell viabilities were tested by cell counting kit (CCK-8) in vitro. There was no obvious cytotoxicity to normal cells, including NIH3T3, RAW264.7, and HUVECs, after incubation with Hf@DAP nanoparticles, indicating biocompatibilities of Hf@DAP nanoparticles. Additionally, a significantly enhanced radiotherapy effect was observed in the N2a cells, a kind of NB cell line, pretreated with Hf@DAP nanoparticles in vitro. The in vivo tumor growth was obviously inhibited in the mice with the combined therapy of Hf@DAP nanoparticles and X-ray, compared with PBS group, Hf@DAP group, and X-ray group. Furthermore, the survival time of the mice in the combined group was significantly prolonged, compared with PBS group. In addition, tissues structures of main organs, such as the lung, liver, spleen, and kidney in these mice, were ordered without the influence of Hf@DAP nanoparticles. Thus, this work proposed a potential radio-sensitizer for further clinical radiotherapy with limited side effects and high efficiency.

Incidences and characteristics of primary lung malignancies in childhood in Germany: An analysis of population-based data from German cancer registries.

Primary lung malignancies are a heterogeneous group of cancers that occur very rarely in childhood. Due to limited knowledge of their epidemiologic and clinical features, these tumors present a challenge to the treating physicians. This study aimed to increase the knowledge about the occurrence of primary lung malignancies in childhood in Germany. Pseudonymized data of cases recorded at the German Center for Cancer Registry Data (ZfKD) between 1990 and 2017 were retrieved. Primary lung malignancies were identified using the ICD- and ICD-O classification. Numbers were compared to those reported to the German Childhood Cancer Registry (GCCR). Crude incidence rates were calculated using the ZfKD database. A total of 168 patients diagnosed with primary lung malignancies in the age below 19 years were identified from the ZfKD. The median age at diagnosis was 13 years. The most common tumor entities were lung carcinoids (n=49), lung carcinoma (n=36), and pleuropulmonary blastoma (n=14). An unexpected accumulation of lung cancer cases was noted in the first year of life without a clearly specified histopathological diagnosis. A substantial discrepancy in the numbers of primary lung malignancies between ZfKD and GCCR was found. We present population-based data on the occurrence of primary childhood lung malignancies in Germany, which were more frequent than previously anticipated but likely remained underreported. For better understanding and optimal treatment of these entities, cancer registration needs to be improved through mandatory reporting to the GCCR and regular data sharing between GCCR, population-based and clinical cancer registries.

Diagnostic Value of Lactate Dehydrogenase and Uric Acid as Screening Tools for Malignancies in Children.

The aim of this study was to determine the diagnostic value of lactate dehydrogenase (LDH) and uric acid (UA) in children undergoing evaluation for possible malignancies. This was a retrospective chart review of patients aged 0 to 18 years presenting to an urban, tertiary care, pediatric hospital between July 1, 2011, and July 1, 2016. Patients were included if they had an LDH and/or UA level drawn, and they were excluded if they had a known cancer diagnosis. Sensitivity, specificity, and receiver operating characteristic curves were calculated for each biomarker. Six hundred five subjects were included in this study; 579 and 384 subjects had LDH and UA levels drawn, respectively; 15.7% had a final diagnosis of malignancy (49 leukemia, 46 nonleukemia). The specificities of both biomarkers for all types of malignancies were lower than their respective sensitivities. Comparing leukemic versus nonleukemic malignancies, the areas under the curve were 0.848 and 0.719, respectively, for LDH and 0.681 and 0.555, respectively, for UA.