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The relatively quiet mutational landscape of rhabdomyosarcoma (RMS) suggests that epigenetic deregulation could be central to oncogenesis and tumour aggressiveness. Histone variants have long been recognised as important epigenetic regulators of gene expression. However, the role of histone variants in RMS has not been studied hitherto. In this study, we show that histone variant H3.3 is overexpressed in alveolar rhabdomyosarcoma (ARMS), an aggressive subtype of RMS. Functionally, knockdown of H3F3A, which encodes for H3.3, significantly impairs the ability of ARMS cells to undertake migration and invasion and reduces Rho activation. In addition, a striking reduction in metastatic tumour burden and improved survival is apparent in vivo. Using RNA-sequencing and ChIP-sequencing analyses, we identified Melanoma Cell Adhesion Molecule (MCAM/CD146) as a direct downstream target of H3.3. Loss of H3.3 resulted in a reduction in the presence of active marks, and an increase in the occupancy of H1 at the MCAM promoter. Cell migration and invasion were rescued in H3F3A-depleted cells through MCAM overexpression. Moreover, we identified G9a, a lysine methyltransferase encoded by EHMT2, as an upstream regulator of H3F3A. Therefore, this study identifies a novel H3.3 dependent axis involved in ARMS metastasis. These findings establish the potential of MCAM as a therapeutic target for high-risk ARMS patients. This article is protected by copyright. All rights reserved.

BACKGROUND The relationship of early catheter-related bloodstream infections (CRBSIs) with perioperative neutropenia and antibiotic prophylaxis is not well established. We sought to evaluate perioperative factors associated with early CRBSIs in newly diagnosed pediatric cancer patients, particularly hematological indices and antibiotic use. METHODS We retrospectively reviewed national registry records of newly diagnosed pediatric cancer patients with port-a-caths inserted using standardized perioperative protocols where only antibiotic use was not regulated. Thirty-day postoperative CRBSI incidence was correlated with preoperative factors using logistic regression and with postoperative blood counts using linear trend analysis. RESULTS Among 243 patients, 17 CRBSIs (7.0%) occurred at median 14 (range, 8-28) postoperative days. Early CRBSIs were significantly associated with cancer type [acute myeloid leukemia and other leukemias (AML/OLs) vs. solid tumors and lymphomas (STLs): odds ratio (OR), 5.09; P = 0.0036; acute lymphoblastic leukemia vs. STL: OR 0.83; P = 0.0446] but not preoperative antibiotics, absolute neutrophil counts and white blood cell counts. Thirty-day postoperative absolute neutrophil counts and white blood cell trends differed significantly between patients with acute lymphoblastic leukemia and STLs (OR 0.83, P < 0.05) and between AML/OLs and STLs (OR 5.09, P < 0.005), with AML/OL patients having the most protracted neutropenia during this period. CONCLUSIONS Contrary to common belief, low preoperative absolute neutrophil counts and lack of preoperative antibiotics were not associated with higher early CRBSI rates. Instead, AML/OL patients, particularly those with prolonged neutropenia during the first 30 postoperative days, were at increased risk. Our findings do not support the use of empirical preoperative antibiotics and instead identify prolonged postoperative neutropenia as a major contributing factor for early CRBSI.

Langerhans cell histiocytosis (LCH) is a potentially fatal neoplasm characterized by the aberrant differentiation of mononuclear phagocytes, driven by mitogen-activated protein kinase (MAPK) pathway activation. LCH cells may trigger destructive pathology yet remain in a precarious state finely balanced between apoptosis and survival, supported by a unique inflammatory milieu. The interactions that maintain this state are not well known and may offer targets for intervention. Here, we used single-cell RNA-seq and protein analysis to dissect LCH lesions, assessing LCH cell heterogeneity and comparing LCH cells with normal mononuclear phagocytes within lesions. We found LCH discriminatory signatures pointing to senescence and escape from tumor immune surveillance. We also uncovered two major lineages of LCH with DC2- and DC3/monocyte-like phenotypes and validated them in multiple pathological tissue sites by high-content imaging. Receptor-ligand analyses and lineage tracing in vitro revealed Notch-dependent cooperativity between DC2 and DC3/monocyte lineages during expression of the pathognomonic LCH program. Our results present a convergent dual origin model of LCH with MAPK pathway activation occurring before fate commitment to DC2 and DC3/monocyte lineages and Notch-dependent cooperativity between lineages driving the development of LCH cells.

Complete upfront resection of pediatric gastrointestinal lymphomas is recommended over biopsy whenever feasible, but either approach may have adverse sequelae. We sought to compare gastrointestinal and oncological outcomes of pediatric gastrointestinal lymphomas who underwent attempted upfront resection or biopsy of the presenting bowel mass. We retrospectively reviewed charts of children with gastrointestinal lymphomas treated on LMB89 and LMB96 protocols from 2000 to 2019 who underwent upfront gastrointestinal surgery, and compared resection and biopsy groups. Of 33 children with abdominal lymphomas, 20 had upfront gastrointestinal surgery—10 each had resection or biopsy. Patients with attempted upfront resections had fewer postoperative gastrointestinal complications compared to biopsies (10% vs. 60%, p = 0.057), but longer time to chemotherapy initiation (median 11.5 vs. 4.5 days, p

INTRODUCTION Children with solid organ tumours often present for curative surgery. Even with the best surgical technique, micrometastases can occur. Preclinical studies support the postulation that neuraxial anaesthesia maintains the body’s immune and inflammatory milieu against metastasis. However, human retrospective adult studies showed varying results, and no study has been done in children. We aimed to find out if intraoperative epidural, perioperative opioid and volatile dose are associated with relapse-free survival (RFS) in children with solid organ tumours. METHODS This is a retrospective cohort study of 126 children from a tertiary paediatric unit who were diagnosed with solid organ tumours (neuroblastoma, hepatoblastoma or sarcoma) over a 16-year period. RFS, stratified by tumour subtypes, was estimated using the Kaplan-Meier method. Adjusted hazard ratios (aHRs) were obtained from multivariable Cox regression models after taking potential covariates into account. RESULTS Of 126 children with solid organ tumours (51.6% neuroblastoma, 34.9% sarcoma and 13.5% hepatoblastoma), 53.2% received combined general anaesthesia (GA)/epidural. A total of 21 (31.3%) and 20 (33.9%) patients relapsed during the study period in the combined GA/epidural group and the GA alone group, respectively. Patients with sarcoma receiving combined GA/epidural had a clinically meaningful lower risk of relapse compared to patients receiving GA alone (aHR 0.51, 95% confidence interval 0.14–1.79), although this was not statistically significant. CONCLUSION Our study demonstrated some clinically meaningful associations, especially in paediatric sarcoma patients. Overall, however, there was no statistically significant association between epidural use and an improved RFS.

Embryonal rhabdomyosarcoma (ERMS) is characterized by a failure of cells to complete skeletal muscle differentiation. Although ERMS cells are vulnerable to oxidative stress, the relevance of mitochondrial calcium homeostasis in oncogenesis is unclear. Here, we show that ERMS cell lines as well as primary tumours exhibit elevated expression of the Mitochondrial Calcium Uniporter (MCU). MCU knockdown resulted in impaired mitochondrial calcium uptake and a reduction in mitochondrial reactive oxygen species (mROS) levels. Phenotypically, MCU knockdown cells exhibited reduced cellular proliferation and motility, with an increased propensity to differentiate in vitro and in vivo. RNA-sequencing of MCU knockdown cells revealed a significant reduction in genes involved in TGFβ signalling that play prominent roles in oncogenesis and inhibition of myogenic differentiation. Interestingly, modulation of mROS production impacted TGFβ signalling. Our study elucidates mechanisms by which mitochondrial calcium dysregulation promotes tumour progression and suggests that targeting the MCU complex to restore mitochondrial calcium homeostasis could be a therapeutic avenue in ERMS.

Laparoscopic surgery has become standard of care in high-income countries but is rarely accessible in low- and middle-income countries (LMICs). This study assessed experience with laparoscopy and attitudes toward a low-cost laparoscopic system among surgeons in sub-Saharan Africa. A survey assessing current laparoscopic practice and feedback on a low-cost laparoscopic system was administered to attendees of the College of Surgeons of East, Central, and Southern Africa (COSECSA) Scientific Conference between December 4 and December 6, 2019 in Kampala, Uganda. Fifty-six surgeons from 14 countries participated. A majority were male (n = 46, 82%) general surgeons (n = 37, 66%) from tertiary/teaching hospitals (n = 36, 64%). For those with training in laparoscopy (n = 33, 59%), 22 (67%) reported less than 1 year of training and over half (n = 17, 52%) reported 1 month or less. Overall, a minority (n = 21, 38%) used laparoscopy in current practice, with 57% (n = 12) of those performing laparoscopy less than once per week. The most common laparoscopic surgeries performed were cholecystectomy (n = 15), diagnostic laparoscopy (n = 14), and appendectomy (n = 12). Few surgeons were performing more complex cases (n = 5). Barriers to laparoscopy included poor access to training equipment (n = 34, 61%), mentors (n = 33, 59%), laparoscopic equipment (n = 31, 55%), equipment maintenance (n = 25, 45%), access to consumable supplies (n = 21, 38%), and cost (n = 31, 55%). Fifty-two participants (93%) were interested in increasing their use of laparoscopy; the majority felt that a low-cost laparoscope (n = 52, 93%) and lift retractor for gasless laparoscopy (n = 46, 82%) would serve an unmet need in their practice. While the use of laparoscopy is currently limited in COSECSA countries, there is a significant interest among surgeons to increase implementation. A low-cost, durable laparoscopic system was viewed as a potential solution to the current barriers and could improve implementation in LMICs.

Aims Congenital mesoblastic nephroma (CMN) is histologically classified into classic, cellular and mixed subtypes. The aims of this study were to characterise the clinical, pathological and molecular features of a series of CMNs, and to determine the utility of pan-Trk and epidermal growth factor receptor (EGFR) immunohistochemistry as surrogate markers for NTRK gene fusions and EGFR internal tandem duplications (ITDs). Methods and results Twenty-two archival CMN cases (12 classic, five cellular, and five mixed) were tested for the ETV6-NTRK3 fusion and EGFR ITD transcripts by the use of reverse transcriptase polymerase chain reaction (PCR), and next-generation sequencing-based anchored multiplex PCR. All 12 classic CMNs had EGFR ITD. Of the five cellular CMNs, four had the ETV6-NTRK3 fusion and one had the KLHL7-BRAF fusion. Of the five mixed CMNs, four had EGFR ITD, and one had the ETV6-NTRK3 fusion. Pan-Trk immunoreactivity was 100% sensitive and 94.1% specific for the presence of NTRK rearrangement. However, EGFR staining was only 62.5% sensitive and 33.3% specific for EGFR ITD. Conclusions EGFR ITD is a consistent genetic event in classic CMN. A majority of cellular CMNs have the ETV6-NTRK3 fusion. Rare cellular CMNs may harbour non-canonical mutations such as the KLHL7-BRAF fusion, which was found in one case. Mixed CMNs may have either EGFR ITD or the ETV6-NTRK3 fusion. Pan-Trk immunohistochemistry is a sensitive, albeit not perfectly specific, marker for NTRK rearrangement. EGFR immunohistochemistry is not helpful as a marker of EGFR ITD.

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient‐derived cell cultures (PDCs) from chemo‐naïve and post–treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo‐response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal‐type gene expression signature and showed upregulation of pro‐angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard‐of‐care cytotoxics at human C max‐equivalent concentrations, MYCN‐amplified and non‐MYCN‐amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients’ responses, and correlated with gene signatures of chemosensitivity. In this translational proof‐of‐concept study, early‐phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug‐response testing., We developed a system to efficiently and consistently generate patient‐derived cultures (PDCs) of neuroblastoma that recapitulated individual patient’s cytogenetic and immunohistochemical features, and phenotypic responses to standard‐of‐care chemotherapy. PDCs predominantly express the gene signature of the recently described neuroblastoma mesenchymal super‐enhancer state. This proof‐of concept provides translational evidence supporting the proposed role of the mesenchymal cell subpopulation in determining clinical treatment response and offers a novel platform for developing personalized ex vivo therapeutic decision‐making strategies for neuroblastoma.

IntroductionNeurotrophic receptor tyrosine kinase fusions cause overexpression or activation of kinase and are believed to confer oncogenic potential in some non-rhabdomyosarcoma soft tissue sarcomas. TRK inhibitors have recently been shown to induce responses in these tumours though current experience with these agents is still limited.Case reportWe report a case of an adolescent with treatment-refractory non-rhabdomyosarcoma soft tissue sarcomas, carrying a novel DCTN1–NTRK1 gene fusion whose progressive disease was treated with multi-kinase and TRK inhibitors. Management and outcome: Our patient was started on pan-TRK inhibitor larotrectinib, as his disease progressed after chemotherapy, radiation therapy and surgery, based on next-generation sequencing test showing DCTN1–NTRK1 gene fusion. He responded quickly to larotrectinib with the improvement of symptoms and reduction of masses. However, this response was short-lived due to the development of acquired solvent front resistance mutation. This patient did not respond to next-generation TRK inhibitor selitrectinib and eventually succumbed to his disease.DiscussionThe initial rapid and drastic response of our patient to larotrectinib was not sustained due to the development of acquired resistance. This case emphasizes the need for upfront and periodic next-generation sequencing testing to guide treatment of patients with refractory non-rhabdomyosarcoma soft tissue sarcomas.

Thyroglossal duct cyst carcinoma (TGDCa) is a rare cause of neck masses in children. Its pathophysiology stems from two main theories. One suggests that the primary carcinoma originated from ectopic thyroid tissue, whilst the other suggest it is a result of metastasis to the thyroglossal duct cyst from the thyroid gland. A case of a 12-year-old girl who presented with a suspicious neck mass and subsequently diagnosed with TGDCa is reported. A literature review was performed and we conclude that aggressive surgical management of a Sistrunk procedure, total thyroidectomy, bilateral tracheoesophageal groove clearance and neck dissection was justified for this child. We found that if the preoperative diagnosis is TGDCa, a more aggressive surgical approach tends to be taken. However, cases of recurrence remain low and a total thyroidectomy does entail a larger morbidity for the pediatric patient. Hence, we do not recommend an aggressive approach routinely. In this review, we extrapolated AJCC data for thyroid malignancies and staged the TGDCa reported in literature in the last 10 years. It showed us that pT3 tumors tend to have a more aggressive surgical course, whilst a pT1 TGDCa tend to receive a more conservative surgical approach.

Treatment refusal and abandonment (TxRA) are major barriers to improving outcomes among children with sarcomas of the extremities as curative treatment options bearing on amputation or disfiguring surgery, particularly in countries with limited resources. A multi-institutional retrospective study was conducted to determine the predictive factors for TxRA among patients with osteosarcoma associated with survival outcomes across Southeast Asia (SEA).Pediatric patients with osteosarcoma treated between January 1998 and December 2017 in four SEA pediatric oncology centers from three countries were studied. Nelson-Aalen estimates, Kaplan-Meier method, and Cox's proportion hazard model were applied to address the cumulative incidence, survival outcomes, and to identify prognostic factors associated with TxRA.From a total of 208 patients with osteosarcoma enrolled; 18 (8.7%) patients refused and 41 (19.7%) patients abandoned treatment. Income classification of countries, age at diagnosis, tumor size, disease extent, chemotherapy protocols, and types of surgery were associated with TxRA. Tumor size more than 15 cm was an independent risk factor associated with TxRA. The 5-year overall and relapse-free survivals were 49.4% and 50.4%, respectively. However, these rates declined further to 37.9% and 35.8%, respectively, when TxRA were considered as events. Tumor size larger than 15 cm and metastatic disease were independent risk factors associated with TxRA-sensitive outcomes.The prevalence of TxRA was high in SEA, particularly in lower middle-income countries. Factors associated with TxRA related to tumor burden. Treatment outcomes could be substantially improved by lowering the refusal and abandonment rates.

Surgical trainees performing subclavian vein (SCV) cannulation often incorrectly perceive needle trajectory and anatomical relations. As surface landmark-based methods derived from adult surgical practice may be less effective in younger patients, we developed and evaluated a novel bony landmark-based method for teaching SCV cannulation for central venous access device (CVAD) placement in children. Over 2 sequential 3-year periods, pediatric surgical trainees were taught infraclavicular SCV cannulation via surface- and bony-landmark approaches, respectively. We prospectively recorded patient, surgeon and operative details on all Hickman line and port-a-cath insertions placed by trainees as the first surgeon via percutaneous infraclavicular SCV puncture and compared procedural outcomes and complications across both periods. Of 271 cases included in the study, trainees performed 52 (50.5%) and 92 (54.8%) procedures in the first and second periods, respectively. Patients in both periods did not differ by gender, disease, CVAD device, or prior CVAD, chemotherapy or infection status. In the second (bony landmark) period, although patients were younger (6.0 vs. 8.7 years, P = 0.003) mean procedural duration was shorter (42.5 vs. 58.3 min, P

Cell lines represent the most versatile and widely used models of cancer and, as such, are critical for identifying and advancing new therapies. Strikingly, there is a significant gap in both the number of childhood brain cancer cell lines and their characterisation compared to their adult counterparts. To address this inequity, we established a childhood brain cancer cell line atlas (publicly available at vicpcc.org.au/dashboard) encompassing over 180 childhood CNS-derived cell lines, representing 20 tumour types and 11 molecular subtypes. Cell lines are characterized by whole genome, RNA-sequencing, phospho- and total proteomics, DNA methylation and ATAC-seq analyses. Multi-omic factor analysis revealed distinct lineage-specified classification of our cell line cohort. In parallel, high throughput drug and CRISPR/Cas9 screens were conducted to map the functional dependencies in over 70 childhood CNS cell lines, including 47 paediatric high grade glioma models. These screens identified both lineage and molecular-subtype specific genetic and drug dependencies, underscoring the utility of this wide-scale approach. Machine based learning approaches to predict genotype-phenotype correlations uncovered distinct paediatric-specific biomarkers of growth dependency, highlighting the unique genetic wiring underlying paediatric CNS tumours. Finally, by integrating functional, molecular and drug profiles of paediatric CNS cell lines, we construct a system to prioritize investigation of novel therapeutic target-biomarkers pairs in specific CNS tumour types.

Wilms tumor demonstrates significant interethnic epidemiological, histological and outcome differences, and is rare and poorly studied among Asians. We compared the clinicopathological, and loss of heterozygosity (LOH) profile and survival outcomes of Asian and non-Asian patients with Wilms tumor. Clinical charts and histological slides from patients with malignant renal tumors over a period of 20 years were retrospectively reviewed. We adapted a genotyping assay to determine 1p36 and 16q21-22 LOH in formalin-fixed paraffin-embedded (FFPE) specimens, and compared these characteristics between Asian and non-Asian patients. Fifty-three (79.1%) Asian and 14 (20.9%) non-Asian patients had Wilms tumors. Compared to non-Asians, Asians were younger (mean 4.6 and 4.0 years, respectively), had more equal gender distribution (female: male = 1.8 and 1.0, respectively), fewer tumors with unfavorable histology (25.0% and 4.1%, respectively, p = 0.05), and less advanced disease at presentation, yet similar nodal metastases rates (16.7% and 18.4%, respectively). No Asian patients had bilateral tumors. Our adapted genotyping assay accurately determined LOH in FFPE specimens

BackgroundDiagnostic biopsies of pediatric anterior mediastinal masses (AMMs) are high-risk procedures in which general anesthesia (GA) is traditionally avoided. However, awareness of historically recognized risk factors and corresponding perioperative management have improved over time and may now no longer strictly preclude the use of GA. Therefore, in this study, we examined the association of anesthetic and surgical risk factors and modalities with resulting procedural and survival outcomes in a current patient cohort.MethodsWe retrospectively reviewed charts of 35 children with AMMs who underwent initial diagnostic biopsies between January 2001 and August 2019, and determined tracheal compression and deviation from archival CT scans and procedural and disease outcomes.ResultsTwenty-three (65%) patients underwent GA while 12 (35%) received sedation. Among patients with available CT measurements, 13 of 25 (52%) had >50% anteroposterior tracheal diameter reduction. Patients with >50% anteroposterior tracheal compression received sedation more frequently (p=0.047) and were positioned upright (p=0.015) compared with patients with ≤50% compression, although 4 of 13 and 9 of 12, respectively, still received GA. Intraoperative adverse events (AEs) occurred in four (11.4%) patients: three received GA, and all were positioned supine or lateral. AEs were not associated with radiographic airway risk factors but were significantly associated with morphine and sevoflurane use (pConclusionsIn a current cohort of pediatric AMM biopsies, patients with >50% anteroposterior tracheal compression were more frequently managed with a conservative perioperative management strategy, though not completely excluding GA. The corresponding reduction in frequency of procedural AEs in this traditionally high-risk group suggests that increased awareness of procedural risk factors and appropriate risk-guided perioperative management choices may obviate the procedural mortality historically associated with pediatric AMM biopsies.

Rhabdomyosarcoma (RMS) is a heterogeneous soft tissue neoplasm most frequently found in children and adolescents. As the prognosis for recurrent and metastatic RMS remains poor, immunotherapies are hoped to improve quality of life and survival. CD137 is a member of tumor necrosis factor receptor family and a T cell costimulatory molecule which induces potent cellular immune responses that are able to eliminate malignant cells. Therefore, it was puzzling to find expression of CD137 on an RMS tissue microarray by multiplex staining. CD137 is not only expressed by infiltrating T cells but also by malignant RMS cells. Functional in vitro experiments demonstrate that CD137 on RMS cells is being transferred to adjacent antigen-presenting cells by trogocytosis, where it downregulates CD137 ligand, and thereby reduces T cell costimulation which results in reduced killing of RMS cells. The transfer of CD137 and the subsequent downregulation of CD137 ligand is a physiological negative feedback mechanism that is likely usurped by RMS, and may facilitate its escape from immune surveillance. In addition, CD137 signals into RMS cells and induces IL-6 and IL-8 secretion, which are linked to RMS metastasis and poor prognosis. However, the ectopic expression of CD137 on RMS cells is an Achilles’ heel that may be utilized for immunotherapy. Natural killer cells expressing an anti-CD137 chimeric antigen receptor specifically kill CD137-expressing RMS cells. Our study implicates ectopic CD137 expression as a pathogenesis mechanism in RMS, and it demonstrates that CD137 may be a novel target for immunotherapy of RMS.

BackgroundHepatocellular carcinoma (HCC) is a rare hepatic malignancy in children. Hepatitis B virus (HBV) infection is a key predisposing factor in endemic regions but its impact on outcome has not been studied. We aim to evaluate the prognostic implication of HBV seropositivity and role of cancer surveillance in children with HCC from East Asian populations with national HBV vaccination.MethodsReview of population-based databases for patients (< 18 years old) diagnosed with HCC from 1993 to 2017 in two Southeast Asian regions with universal HBV vaccination (instituted since 1988 and 1987 in Hong Kong and Singapore, respectively).ResultsThirty-nine patients were identified (Hong Kong, 28; Singapore, 11). Thirty were male; median age at diagnosis was 10.8 years (range, 0.98–16.6). Abdominal pain was the commonest presentation while five patients were diagnosed through surveillance for underlying condition. Alpha-fetoprotein was raised in 36 patients (mean, 500,598 ng/ml). Nineteen had bilobar involvement, among the patients in whom pretreatment extent of disease (PRETEXT) staging could retrospectively be assigned, 3 had stage I, 13 had stage II, 4 had stage III, and 11 had stage IV disease. Seventeen had distant metastasis. HBsAg was positive in 19 of 38 patients. Two patients had fibrolamellar HCC. Upfront management involved tumor resection in 16 (liver transplantation, 2), systemic chemotherapy in 21, interventional procedures in 6 [transarterial chemoembolization (TACE), 5, radiofrequency ablation (RFA), 1], and radiotherapy in 4 (selective internal radiation, 3, external beam radiation, 1). Five-year event-free survival (EFS) and overall survival (OS) were 15.4 ± 6.0 and 26.1 ± 7.2%, respectively. Patient’s HBsAg positivity, metastatic disease and inability to undergo definitive resection represent poor prognostic factors in univariate and multivariable analyses. Patients diagnosed by surveillance had significantly better outcome.ConclusionPediatric HCC has poor outcome. HBV status remains relevant in the era of universal HBV vaccination. HBV carrier has inferior outcome and use of surveillance may mitigate disease course.

PURPOSEPediatric solid tumors require coordinated multidisciplinary specialist care. However, expertise and resources to conduct multidisciplinary tumor boards (MDTBs) are lacking in low- and middle-income countries (LMICs). We aimed to profile the landscape of pediatric solid tumor care and practices and perceptions on MDTBs among pediatric solid tumor units (PSTUs) in Southeast Asian LMICs.METHODSUsing online surveys, availability of specialty manpower and MDTBs among PSTUs was first determined. From the subset of PSTUs with MDTBs, one pediatric surgeon and one pediatric oncologist from each center were queried using 5-point Likert scale questions adapted from published questionnaires.RESULTSIn 37 (80.4%) of 46 identified PSTUs, availability of pediatric-trained specialists was as follows: oncologists, 94.6%; surgeons, 91.9%; radiologists, 54.1%; pathologists, 40.5%; radiation oncologists, 29.7%; nuclear medicine physicians, 13.5%; and nurses, 81.1%. Availability of pediatric-trained surgeons, radiologists, and pathologists was significantly associated with the existence of MDTBs ( P = .037, .005, and .022, respectively). Among 43 (89.6%) of 48 respondents from 24 PSTUs with MDTBs, 90.5% of oncologists reported > 50% oncology-dedicated workload versus 22.7% of surgeons. Views on benefits and barriers did not significantly differ between oncologists and surgeons. The majority agreed that MDTBs helped to improve accuracy of treatment recommendations and team competence. Complex cases, insufficient radiology and pathology preparation, and need for supplementary investigations were the top barriers.CONCLUSIONThis first known profile of pediatric solid tumor care in Southeast Asia found that availability of pediatric-trained subspecialists was a significant prerequisite for pediatric MDTBs in this region. Most PSTUs lacked pediatric-trained pathologists and radiologists. Correspondingly, gaps in radiographic and pathologic diagnoses were the most common limitations for MDTBs. Greater emphasis on holistic multidisciplinary subspecialty development is needed to advance pediatric solid tumor care in Southeast Asia.

Digital real-time PCR assay rapidly measures single telomere lengths and uncovers telomere maintenance mechanisms in cancer., Telomere length is a promising biomarker for age-associated diseases and cancer, but there are still substantial challenges to routine telomere analysis in clinics because of the lack of a simple and rapid yet scalable method for measurement. We developed the single telomere absolute-length rapid (STAR) assay, a novel high-throughput digital real-time PCR approach for rapidly measuring the absolute lengths and quantities of individual telomere molecules. We show that this technique provides the accuracy and sensitivity to uncover associations between telomere length distribution and telomere maintenance mechanisms in cancer cell lines and primary tumors. The results indicate that the STAR assay is a powerful tool to enable the use of telomere length distribution as a biomarker in disease and population-wide studies.

Background Pediatric solid tumors require coordinated multidisciplinary specialist care. However, expertise and resources to conduct multidisciplinary tumor board (MDTB) meetings are lacking in low- and middle-income countries (LMICs). We aimed to profile practices and perceptions on MDTBs among pediatric solid tumor units (PSTUs) in Southeast Asian LMIC countries. Methods Using online survey forms, availability of specialty manpower and MDTBs among PSTUs was first determined. From the subset of PSTUs with MDTBs, 1 pediatric surgeon and 1 pediatric oncologist from each center were queried using 5-point Likert scale questions adapted from published questionnaires. Results In 37/46 (80.4%) identified PSTUs, pediatric-trained oncologists, surgeons, radiologists, pathologists, radiation oncologists, nuclear medicine physicians and nurses were available in 94.6%, 91.9%, 54.1%, 40.5%, 29.7%, 13.5% and 81.1% of PSTUs, respectively. Availability of pediatric-trained surgeons, radiologists and pathologists were significantly associated with existence of MDTBs (p=0.037, 0.005, 0.022 respectively). Among 43/48 (89.6%) respondents from 24 PSTUs with MDTBs, 90.5% of oncologists reported >50% oncology-dedicated workload versus 22.7% of surgeons. Views on benefits and barriers did not significantly differ between both groups. Majority agreed MDTBs helped improve accuracy of treatment recommendations and team competence. Complex cases, insufficient radiology and pathology preparation, and need for supplementary investigations, were the top barriers. Conclusions Availability of pediatric-trained subspecialists was a significant prerequisite for pediatric MDTBs. Most PSTUs lacked pediatric-trained pathologists and radiologists. Correspondingly, gaps in radiographic and pathological diagnoses were the commonest limitations. Greater emphasis on holistic multidisciplinary subspecialty development is needed to advance pediatric solid tumor care in Southeast Asia.

We describe the clinical, pathological, and molecular features of a primary adrenal angiomatoid fibrous histiocytoma (AFH) in an 11-year-old girl presenting with pyrexia of unknown origin. We performed next-generation sequencing-based anchored multiplex polymerase chain reaction (Archer® FusionPlex® sarcoma assay), which revealed an EWSR1-ATF1 gene fusion with novel breakpoints in exon 11 of EWSR1 and exon 3 of ATF1. The pyrexia resolved fully after surgical resection, and the patient was disease-free on follow-up at 1 year and 6 months. This case exemplifies the value of molecular testing of pediatric neoplasms presenting at unusual sites for diagnosis and identification of novel gene fusion breakpoints.

Clear cell sarcoma of the kidney (CCSK) is a rare paediatric renal malignant tumour. The majority of CCSKs have internal tandem duplications (ITDs) of the BCOR gene, whereas a minority have the YWHAE-NUTM2 gene fusion. A third 'double-negative' (DN) category comprises CCSKs with neither BCOR ITDs nor YWHAE-NUTM2 fusion. The aim of this study was to characterise 11 histologically diagnosed CCSKs immunohistochemically (with CCND1, BCOR and CCNB3 stains) and genetically.By next-generation sequencing, 10 cases (90.9%) had BCOR exon 15 ITDs, with positive BCOR immunoreactivity being found in four (36%) or eight (72%) cases, depending on the antibody clone. By reverse transcription polymerase chain reaction, none had the YWHAE-NUTM2 fusion. The DN case had a BCOR-CCNB3 fusion and strong nuclear CCNB3 and BCOR immunoreactivity. Quantitative polymerase chain reaction showed markedly elevated BCOR expression in this case, whereas BCOR ITD cases had lower levels of elevated BCOR expression.The majority of the CCSKs in our cohort had BCOR ITDs, and none had the YWHAE-NUTM2 fusion. We verified the strong, diffuse cyclin D1 (CCND1) immunoreactivity in CCSKs described in recent reports. BCOR immunoreactivity was not consistently positive in all CCSKs with BCOR ITDs, and therefore cannot be used as a diagnostic immunohistochemical stain to identify BCOR ITD cases. The DN case was a BCOR-CCNB3 fusion sarcoma. BCOR-CCNB3 sarcoma is typically a primary bone sarcoma affecting male adolescents, and this is the first report of it presenting in a kidney of a young child as a CCSK. The full spectrum of DN CCSKs awaits more comprehensive characterisation.

Laparoscopy offers many benefits to splenectomy, such as reduced incisional pain and shortened hospital duration. The purpose of this study is to evaluate procedural and outcome differences between multiport (MP) and reduced port (RP) splenectomy when utilized to treat children.An institutional review board approved retrospective analysis of all consecutive laparoscopic total splenectomies performed at a single institution between January 2010 and October 2015 was conducted. We evaluated demographics, surgical technique, instance of conversion, operative duration, estimated blood loss, need for intraoperative blood transfusion, postoperative length of stay, time to full feeds, complications, and follow-up duration.Over a 5-year period, 66 patients less than 20 years of age underwent laparoscopic total splenectomy. RP splenectomy was attempted in 14 patients. The remaining 52 were MP operations. Populations were comparable with regard to demographics. Preoperative splenic volumes (mL) were greater in the RP population (median [IQR]: 1377 [747-1508] versus 452 [242-710], P = .039). RP splenectomy demonstrated no difference compared to MP splenectomy in operative time (153 versus 138 minutes, P = .360), estimated blood loss (120 versus 154 mL, P = .634), or percent of cases requiring intraoperative blood transfusion (14 versus 23, P = .716). By the first postoperative day, 57% of RP and 17% of MP patients could be discharged (P = .005). Thirty-day readmission rates were similar, at 7% for RP and 8% for MP operations. Fever was the indication for all readmissions. Mean duration of follow-up is 28 months for MP and 13 months for RP cases.A reduced number of ports can be safely utilized for total splenectomy in pediatric patients without increasing procedural duration or need for intraoperative blood transfusion. In addition, rate of discharge on the first postoperative day was significantly higher in the RP splenectomy group.

Introduction Primary spontaneous pneumothorax (PSP) and its high recurrence rate pose a therapeutic challenge to both patients and their managing surgeons. Mechanical or chemical pleurodesis can be used to prevent recurrence, but the optimal treatment often remains a matter of debate. This meta-analysis aims to compare the outcomes between mechanical and chemical pleurodesis following bullectomy for PSP. Materials and Methods Studies published up to 2019 were searched from Medline, Embase, Google Scholar, and Cochrane databases. A meta-analysis of randomized controlled trials (RCTs) and observational cohort studies (OCSs) comparing outcomes between mechanical and chemical pleurodesis for PSP was performed. Results Seven studies (one RCT and six OCSs) were included, comprising 1,032 cases of mechanical (799 abrasions, 202 pleurectomies, and 31 unspecified abrasions/pleurectomies/both), and 901 cases of chemical (643 talc, 69 minocycline, and 189 unspecified talc/kaolin) pleurodesis. The recurrence rate of pneumothorax after chemical pleurodesis (1.2%) was significantly lower than mechanical pleurodesis (4.0%) (pooled odds ratio [OR] = 3.00; 95% confidence interval [CI] = 1.59–5.67; p = 0.0007; I 2 = 19%). Hospital stay was also slightly shorter in the chemical pleurodesis group (pooled mean difference [MD] = 0.42 days; 95% CI = 0.12–0.72; p = 0.005; I 2 = 0%). There was no statistically significant difference in postoperative complications (pooled OR = 1.18; 95%CI = 0.40–3.48; p = 0.76; I 2 = 71%) and operative time (pooled MD = 3.50; 95%CI = −7.28 to 14.28; p = 0.52; I 2 = 99%) between these two groups. Conclusion Chemical pleurodesis is superior to mechanical pleurodesis following bullectomy for PSP in reducing hospital stay and recurrence rate. However, more RCTs with longer follow-up are necessary to demonstrate the benefit of chemical pleurodesis for PSP.

Apoptosis (programmed cell death) is a systematic and coordinated cellular process that occurs in physiological and pathophysiological conditions. Sidestepping or resisting apoptosis is a distinct characteristic of human cancers including childhood malignancies. This review dissects the apoptosis pathways implicated in pediatric tumors. Understanding these pathways not only unraveled key molecules that may serve as potential targets for drug discovery, but also molecular nodes that integrate with other signaling networks involved in processes such as development. This review presents current knowledge of the complex regulatory system that governs apoptosis with respect to other processes in pediatric cancers, so that fresh insights may be derived regarding treatment resistance or for more effective treatment options.

Osteosarcoma (OS) and the Ewing sarcoma family of tumors (ESFT) are the most common primary pediatric bone malignancies. We sought to assess the diagnostic accuracy of initial tumor biopsies in patients with OS or ESFT at a pediatric cancer center.All biopsies performed at initial presentation of patients with OS or ESFT at our institution from 2003 to 2012 were retrospectively reviewed. Diagnostic accuracy and incidence of complications were correlated with study variables using logistic regression analysis.One hundred forty-two biopsies were performed in 105 patients (median age 13.4years, range: 1.8-23.0), 104 (73.2%) OS and 38 (27.8%) ESFT. Thirty-one (21.8%) were performed on metastatic sites. Eighty-five (76.6%) of 111 primary site biopsies were open procedures, and 26 were percutaneous (23.4%). Primary site biopsies were successful in 94.1% of open and 73.1% of percutaneous procedures. Odds of obtaining a successful diagnostic specimen were 7.8 times higher with open approach (CI: 1.6-36.8). Metastatic site biopsies were successful in 66.7% of percutaneous and 100% of open and thoracoscopic procedures.Biopsy of metastatic sites was equal to primary site in obtaining diagnostic material with the added benefit of accurate staging, with few adverse events and high diagnostic yield.

Neuroblastoma is an aggressive, relapse-prone childhood tumor of the sympathetic nervous system. Current treatment modalities do not fully exploit the genetic basis between the different molecular subtypes and little is known about the targets discovered in recent mutational and genetic studies. Neuroblastomas with poor prognosis are often characterized by 1p36 deletion, containing the kinesin gene KIF1B. Its beta isoform, KIF1Bβ, is required for NGF withdrawal-dependent apoptosis, mediated by the induction of XIAP-associated Factor 1 (XAF1). Here, we showed that XAF1 low expression correlates with poor survival and disease status. KIF1Bβ deletion results in loss of XAF1 expression, suggesting that XAF1 is indeed a downstream target of KIF1Bβ. XAF1 silencing protects from NGF withdrawal and from KIF1Bβ-mediated apoptosis. Overexpression of XAF1 impairs tumor progression whereas knockdown of XAF1 promotes tumor growth, suggesting that XAF1 may be a candidate tumor suppressor in neuroblastoma and its associated pathway may be important for developing future interventions.

Assessment of cancer predisposition syndromes (CPS) in childhood tumours is challenging to paediatric oncologists due to inconsistent recognizable clinical phenotypes and family histories, especially in cohorts with unknown prevalence of germline mutations. Screening checklists were developed to facilitate CPS detection in paediatric patients; however, their clinical value have yet been validated. Our study aims to assess the utility of clinical screening checklists validated by genetic sequencing in an Asian cohort of childhood tumours. We evaluated 102 patients under age 18 years recruited over a period of 31 months. Patient records were reviewed against two published checklists and germline mutations in 100 cancer-associated genes were profiled through a combination of whole-exome sequencing and multiplex ligation-dependent probe amplification on blood-derived genomic DNA. Pathogenic germline mutations were identified in ten (10%) patients across six known cancer predisposition genes: TP53, DICER1, NF1, FH, SDHD and VHL. Fifty-four (53%) patients screened positive on both checklists, including all ten pathogenic germline carriers. TP53 was most frequently mutated, affecting five children with adrenocortical carcinoma, sarcomas and diffuse astrocytoma. Disparity in prevalence of germline mutations across tumour types suggested variable genetic susceptibility and implied potential contribution of novel susceptibility genes. Only five (50%) children with pathogenic germline mutations had a family history of cancer. We conclude that CPS screening checklists are adequately sensitive to detect at-risk children and are relevant for clinical application. In addition, our study showed that 10% of Asian paediatric solid tumours have a heritable component, consistent with other populations., Cancer: Screening checklists catch Asian children at risk of hereditary tumours Existing checklists designed to screen children for a genetic predisposition to cancer are sensitive enough to detect at-risk individuals in an Asian population. Joanne Ngeow from the National Cancer Centre Singapore and colleagues reviewed the medical records of 102 paediatric patients diagnosed with cancer and profiled for inherited mutations in 100 cancer-associated genes. They crosschecked the records against two published screening instruments used by clinical geneticists to identify patients with a hereditary cancer risk. Although only ten patients harboured known cancer predisposition mutations, the checklists flagged 54 individuals. However, all ten pathogenic gene carriers screened positive on the diagnostic aids. The checklists thus seem to err on the side of over-identification and don’t miss many true cases of hereditary cancer in this Asian population.

Background/objectives Variations in vascular anatomy (VIVAs) of the retroperitoneal great vessels are uncommon but can potentially complicate surgical procedures and negatively affect treatment outcomes, yet their incidence and clinical impact are poorly studied. We sought to assess the incidence and clinical impact of VIVAs of retroperitoneal great vessels in patients with retroperitoneal tumors. Methods We retrospectively analyzed imaging, surgical, treatment and survival data of all pediatric patients with retroperitoneal tumors who underwent resection between January 2007 and October 2016, comparing preoperative scans with corresponding intraoperative observations, and subsequent surgical outcomes. Results Among 66 children with renal, adrenal and paravertebral tumors, 6 (9%) had retroperitoneal VIVAs. Retroperitoneal VIVAs were present only with right-sided tumors and significantly associated with more frequent intraoperative complications (P = 0.013). While the presence of retroperitoneal VIVAs was not directly associated with survival outcomes, relapse was more frequent in patients with VIVAs (33%) than those without (18.3%, P = 0.378), and relapse was also associated with lower overall and event-free survival (P Conclusions VIVAs of retroperitoneal great vessels occurred in 9% of our patients with retroperitoneal tumors. Retroperitoneal VIVAs were associated with higher rates of intraoperative complications and disease relapse but was not directly related to survival outcomes. Type of Study: Retrospective review study. Level of evidence Level III Retrospective comparative study.

Lead discovery in osteosarcoma has been hampered by the lack of new agents, limited representative clinical samples and paucity of accurate preclinical models. We developed orthotopic patient-derived xenografts (PDXs) that recapitulated the molecular, cellular and histologic features of primary tumors, and screened PDX-expanded short-term cultures and commercial cell lines of osteosarcoma against focused drug libraries. Osteosarcoma cells were most sensitive to HDAC, proteasome, and combination PI3K/MEK and PI3K/mTOR inhibitors, and least sensitive to PARP, RAF, ERK and MEK inhibitors. Correspondingly, PI3K signaling pathway genes were up-regulated in metastatic tumors compared to primary tumors. In combinatorial screens, as a class, HDAC inhibitors showed additive effects when combined with standard-of-care agents gemcitabine and doxorubicin. This lead discovery strategy afforded a means to perform high-throughput drug screens of tumor cells that accurately recapitulated those from original human tumors, and identified classes of novel and repurposed drugs with activity against osteosarcoma.

Pathological diagnosis of clear cell sarcoma of the kidney (CCSK) is challenging as it resembles blastemal Wilms tumor (WT) and other pediatric sarcomas, and does not have any distinctive immunophenotype. The YWHAE-FAM22 translocation t(10;17)(q22;p13) has been reported in a subset of CCSK. This translocation also occurs in high-grade endometrial sarcoma, in which it is associated with cyclin D1 overexpression. Hence we seek to determine YWHAE-FAM22 translocation status and cyclin D1 immunoreactivity in a series of local CCSK cases. Of 8 CCSK cases from 7 patients identified, no CCSK had the YWHAE-FAM22 fusion transcript by reverse transcriptase–polymerase chain reaction. Novel karyotypes were identified for 2 cases: 1 had t(2;13)(q13; q22) and the other t(3:17)(q29;p11.2). Excluding a case with poor tissue section antigenicity, 7 of 7 CCSKs (100%) showed diffuse and strong nuclear cyclin D1 staining. Cyclin D1 immunohistochemistry was also performed on tissue microarrays of other pediatric renal tumors: blastemal areas of 18 WT cases were negative; 6 rhabdoid tumors and 1 metanephric adenoma showed patchy and weak staining; 3 mesoblastic nephromas and 18 of 29 neuroblastomas had positive staining. Cyclin D1 immunohistochemistry helps distinguish CCSK from blastemal WT and metanephric adenoma and rhabdoid tumors, but not from neuroblastomas and mesoblastic nephromas. Cyclin D1 overexpression in CCSK is not contingent on YWHAE-FAM22 translocation, and cyclin D1 inhibition may potentially be explored as a targeted therapeutic strategy in CCSK.

Background The long-term physiologic and oncologic outcomes of treatment for inferior vena cava (IVC) thrombosis in children with malignant abdominal tumors are unclear. Methods We conducted a retrospective review of children with malignant IVC tumor thrombosis treated at our institution between January 1996 and December 2011. Extent of tumor thrombus was classified using the Hinman system. Disease stage, management, and oncologic and physiologic outcomes and complications were evaluated. Results We identified 15 patients (median age, 4.7years): 12 with Wilms tumor, 2 with hepatoblastoma, and 1 with adrenocortical carcinoma. Neoadjuvant chemotherapy changed Hinman levels in 2 (13%) patients. IVC thrombus resection was complete in 6 (40%) patients, partial in 7 (47%) patients, and not performed in 1 (6.7%) patient. On follow-up imaging, 8 (53%) patients' IVCs were patent, 6 (40%) had residual thrombus, and 1 (6.7%) was surgically interrupted. Three (20%) patients had perioperative complications, and 2 (13%) experienced transient effects related to IVC occlusion. Conclusions Surgical management of tumor thrombus in the vena cava of children with solid abdominal tumors is challenging. Evidence on which to base strong treatment recommendations is lacking. Few long-term physiologic complications were observed.

Renal masses in children may be discovered during routine clinical examination or incidentally during the course of diagnostic or therapeutic procedures for other causes. Renal cancers are rare in the pediatric population and include a spectrum of pathologies that may challenge the clinician in choosing the optimal treatment. Correct identification of the lesion may be difficult, and the appropriate surgical procedure is paramount for lesions suspected to be malignant. The purpose of this article is to provide a comprehensive overview regarding the spectrum of renal tumors in the pediatric population, both benign and malignant, and their surgical management.

BACKGROUND: Tumor biopsies are central to the diagnosis and management of cancer and are critical to efforts in personalized medicine and targeted therapeutics. In the current study, the authors sought to evaluate the safety and accuracy of biopsies in children with cancer. METHODS: All biopsies performed in children at the study institution with a suspected or established diagnosis of cancer from 2003 through 2012 were reviewed retrospectively. Patient characteristics and disease-related and procedure-related factors were correlated with procedure-related complications and diagnostic accuracy using logistic regression analysis. RESULTS: A total of 1073 biopsies were performed in 808 patients. Of 1025 biopsies with adequate follow-up, 79 (7.7%) were associated with an adverse event, 35 (3.4%) of which were minor (grade 1-2) and 32 (3.1%) of which were major (grade 3-4) (grading was performed according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). The most common major adverse events were blood transfusion (>10 mL/kg; 24 cases) and infection requiring intravenous antibiotics (6 cases). Eleven deaths (1.4%) occurred within 30 days after the procedure, but the procedure may have contributed to the outcome in only 2 cases. A total of 926 biopsies (90.3%) provided definitive histologic diagnoses. Using multivariable analysis, biopsy site, preprocedure hematocrit level, and body mass index were found to be associated with the risk of postprocedural complications (P

Background Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors of the adrenal glands and paraganglia, occurring sporadically or as a range of hereditary tumor syndromes. About 30% of PPGLs are attributed to germline mutations. Clinical presentation, including localization, malignant potential, and age of onset, varies depending on the genetic background. Genetic testing for PPGLs is not well studied in Southeast Asia. We reviewed clinical management of PPGLs in Singapore, highlighting current gaps in clinical practice. Methods Medical records of patients with PPGLs between 2005 and 2016 were reviewed. Diagnosis was confirmed histologically and stratified into sporadic or familial/syndromic (FS). Results Twenty-seven (21.8%) patients were referred to the Cancer Genetics Service (CGS). FS PPGLs (18.5%) and extra-adrenal PPGLs (58.1%) incidences were higher than previous studies. Referrals were lower for sporadic PPGLs compared to FS PPGLs (3.7% vs. 100%). Referrals were highest at diagnosis age