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Brugia malayi, a parasitic nematode that causes lymphatic filariasis, harbors endosymbiotic intracellular bacteria, Wolbachia, that are required for the development and reproduction of the worm. The essential nature of this endosymbiosis led to the development of anti-Wolbachia chemotherapeutic approaches for the treatment of human filarial infections. Our study is aimed at identifying specific proteins that play a critical role in this endosymbiotic relationship leading to the identification of potential targets in the adult worms. Filarial cysteine proteases are known to be involved in molting and embryogenesis, processes shown to also be Wolbachia dependent. Based on the observation that cysteine protease transcripts are differentially regulated in response to tetracycline treatment, we focused on defining their role in symbiosis. We observe a bimodal regulation pattern of transcripts encoding cysteine proteases when in vitro tetracycline treated worms were examined. Using tetracycline-treated infertile female worms and purified embryos we established that the first peak of the bimodal pattern corresponds to embryonic transcripts while the second takes place within the hypodermis of the adult worms. Localization studies of the native proteins corresponding to Bm-cpl-3 and Bm-cpl-6 indicate that they are present in the area surrounding Wolbachia, and, in some cases, the proteins appear localized within the bacteria. Both proteins were also found in the inner bodies of microfilariae. The possible role of these cysteine proteases during development and endosymbiosis was further characterized using RNAi. Reduction in Bm-cpl-3 and Bm-cpl-6 transcript levels was accompanied by hindered microfilarial development and release, and reduced Wolbachia DNA levels, making these enzymes strong drug target candidates.

Background: Patients with relapsed rhabdomyosarcoma (RMS) are treated with varying approaches and have a poor overall survival (OS). We performed an observational comparison of salvage regimens exploring whether high-dose alkylator combinations were associated with longer OS., Procedure: We categorized 110 patients with relapsed RMS from five institutions into two groups, those treated with regimens including a high-dose alkylator (Group A) and those treated without a high-dose alkylator (Group B). We compared OS between the two, adjusting for risk group at diagnosis and institution using Kaplan-Meier and Cox proportional hazards analyses., Results: Median follow-up in the 32 survivors was 4 years (range: 1.0-16.7 years) with a 28% (95% CI: 19%-37%) 4-year OS. Group A patients had a longer OS compared to Group B (4-year OS 41%, 95% CI: 27%-58%, vs. 14%, 95% CI: 4%-24%, respectively, p = 0.002). Adjustment for risk group at diagnosis abrogated the association (HR 1.4, 95% CI: 0.8-2.3, p = 0.16), while controlling for institution had no effect. In stratified analyses, patients with low risk at diagnosis had the highest effect size, suggesting a benefit after high-dose alkylator regimens (stratified HR 4.4, 95% CI: 0.96-20.3, p = 0.06, reference Group A) compared to intermediate- (stratified HR 1.6, 95% CI: 0.9-3.2, p = 0.13) or high- (stratified HR 0.9, 95% CI: 0.4-1.8, p = 0.7) risk patients., Conclusions: Patients with relapsed RMS and low-risk group at diagnosis may benefit from high-dose alkylator chemotherapy, while the high-risk group has a dismal outcome regardless of treatment selection. It is inconclusive whether intermediate-risk patients may benefit from such therapy., (© 2024 Wiley Periodicals LLC.)

Purpose: The combination of gemcitabine and docetaxel is often used to treat patients with recurrent osteosarcoma. Nab-paclitaxel has preclinical activity against osteosarcoma and is potentially less myelosuppressive than docetaxel. We conducted a prospective multi-institutional phase II trial combining gemcitabine and nab-paclitaxel for patients aged 12 to 30 years with recurrent osteosarcoma and measurable disease., Patients and Methods: A Simon's two-stage design was used to test a 4-month progression-free survival (PFS-4) of 10% vs. 35%. Patients received nab-paclitaxel 125 mg/m2 and gemcitabine 1,000 mg/m2 weekly × 3 in 4-week cycles. Immunohistochemical analysis of archival tissue and serial assessment of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) using ultralow passage whole-genome sequencing were performed to identify potential biomarkers of response., Results: Eighteen patients received 56 total cycles (median 2, range 1-12). Two patients (11%) experienced confirmed partial response and six (33%) received >2 cycles. The PFS-4 was 28% (95% confidence interval, 13%-59%). Six patients required dose reductions and three patients were removed due to toxicities. All 18 patients had detectable CTCs and 10 had ctDNA identified. All eight patients with MYC amplification at study entry experienced disease progression., Conclusions: Gemcitabine and nab-paclitaxel demonstrated similar clinical activity and toxicity compared to previous retrospective reports utilizing gemcitabine and docetaxel in patients with recurrent osteosarcoma. Serial analysis of CTC and ctDNA was feasible in this prospective multi-institution study and provides preliminary data on the use of these assays in patients with relapsed disease., (©2024 American Association for Cancer Research.)

Background: Pediatric patients with metastatic and/or recurrent solid tumors have poor survival outcomes despite standard-of-care systemic therapy. Stereotactic ablative radiation therapy (SABR) may improve tumor control. We report the outcomes with the use of SABR in our pediatric solid tumor population., Methods: This was a single-institutional study in patients < 30 years treated with SABR. The primary endpoint was local control (LC), while the secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicity. The survival analysis was performed using Kaplan-Meier estimates in R v4.2.3., Results: In total, 48 patients receiving 135 SABR courses were included. The median age was 15.6 years (interquartile range, IQR 14-23 y) and the median follow-up was 18.1 months (IQR: 7.7-29.1). The median SABR dose was 30 Gy (IQR 25-35 Gy). The most common primary histologies were Ewing sarcoma (25%), rhabdomyosarcoma (17%), osteosarcoma (13%), and central nervous system (CNS) gliomas (13%). Furthermore, 57% of patients had oligometastatic disease (≤5 lesions) at the time of SABR. The one-year LC, PFS, and OS rates were 94%, 22%, and 70%, respectively. No grade 4 or higher toxicities were observed, while the rates of any grade 1, 2, and 3 toxicities were 11.8%, 3.7%, and 4.4%, respectively. Patients with oligometastatic disease, lung, or brain metastases and those who underwent surgery for a metastatic site had a significantly longer PFS. LC at 1-year was significantly higher for patients with a sarcoma histology (95.7% vs. 86.5%, p = 0.01) and for those who received a biological equivalent dose (BED10) > 48 Gy (100% vs. 91.2%, p = 0.001)., Conclusions: SABR is well tolerated in pediatric patients with 1-year local failure and OS rates of <10% and 70%, respectively. Future studies evaluating SABR in combination with systemic therapy are needed to address progression outside of the irradiated field.

Competing Interests: The authors declare no competing interests.

Background and Objectives: Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) are rare vascular tumors in children historically associated with significant morbidity and mortality. This study was conducted to determine first-line therapy in the absence of available prospective clinical trials., Methods: Patients from 17 institutions diagnosed with KHE/TA between 2005 and 2020 with more than 6 months of follow-up were included. Response rates to sirolimus and vincristine were compared at 3 and 6 months. Durability of response and response to other treatment modalities were also evaluated., Results: Of 159 unique KHE/TA subjects, Kasabach-Merritt phenomenon (KMP) was present in 64 (40.3%), and only two patients were deceased (1.3%). Over 60% (n = 96) demonstrated treatment response at 3 months, and more than 70% (n = 114) by 6 months (no significant difference across groups). The vincristine group had higher radiologic response at 3 months compared to sirolimus (72.7% vs. 20%, p = .03), but there were no differences between these groups at 6 months. There were no differences in rates of recurrent or progressive disease between vincristine and sirolimus., Conclusions: In this large, multicenter cohort of 159 patients with KHE/TA, rates of KMP were consistent with historical literature, but the mortality rate (1.3%) was much lower. Overall treatment response rates were high (>70%), and there was no significant difference in treatment response or durability of disease comparing sirolimus to vincristine. Our results support individualized treatment decision plans depending on clinical scenario and patient/physician preferences. Response criteria and response rates reported here will be useful for guiding future treatment protocols for vascular tumors., (© 2023 Wiley Periodicals LLC.)

Ewing sarcoma is a translocation-associated sarcoma mainly impacting adolescents and young adults. The classic translocation (EWSR1::FLI1) leads to a fusion oncoprotein that functions as an aberrant transcription factor. As such, the oncogenic driver of this disease has been difficult to target pharmacologically and, therefore, the systemic therapies used to treat patients with Ewing sarcoma have typically been non-selective cytotoxic chemotherapy agents. The current review highlights recent clinical trials from the last decade that provide the evidence base for contemporary drug therapy for patients with Ewing sarcoma, while also highlighting novel therapies under active clinical investigation in this disease. We review recent trials that have led to the establishment of interval-compressed chemotherapy as an international standard for patients with newly diagnosed localized disease. We further highlight recent trials that have shown a lack of demonstrable benefit from high-dose chemotherapy or IGF-1R inhibition for patients with newly diagnosed metastatic disease. Finally, we provide an overview of chemotherapy regimens and targeted therapies used in the management of patients with recurrent Ewing sarcoma., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Purpose: RAS genes (HRAS, KRAS, and NRAS) are commonly found to be mutated in cancers, and activating RAS variants are also found in disorders of somatic mosaicism (DoSM). A survey of the mutational spectrum of RAS variants in DoSM has not been performed., Methods: A total of 938 individuals with suspected DoSM underwent high-sensitivity clinical next-generation sequencing-based testing. We investigated the mutational spectrum and genotype-phenotype associations of mosaic RAS variants., Results: In this article, we present a series of individuals with DoSM with RAS variants. Classic hotspots, including Gly12, Gly13, and Gln61 constituted the majority of RAS variants observed in DoSM. Furthermore, we present 12 individuals with HRAS and KRAS in-frame duplication/insertion (dup/ins) variants in the switch II domain. Among the 18.3% individuals with RAS in-frame dup/ins variants, clinical findings were mainly associated with vascular malformations. Hotspots were associated with a broad phenotypic spectrum, including vascular tumors, vascular malformations, nevoid proliferations, segmental overgrowth, digital anomalies, and combinations of these. The median age at testing was higher and the variant allelic fraction was lower in individuals with in-frame dup/ins variants than those in individuals with mosaic RAS hotspots., Conclusion: Our work provides insight into the allelic and clinical heterogeneity of mosaic RAS variants in nonmalignant conditions., Competing Interests: Conflict of Interest The authors declare no conflicts of interest., (Copyright © 2022 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

Next-generation sequencing (NGS) assays can sensitively detect somatic variation, and increasingly can enable the identification of complex structural rearrangements. A subset of infantile spindle cell sarcomas, particularly congenital mesoblastic nephromas with classic or mixed histology, have structural rearrangement in the form of internal tandem duplications (ITD) involving EGFR. We performed prospective analysis to identify EGFR ITD through clinical or research studies, as well as retrospective analysis to quantify the frequency of EGFR ITD in pediatric sarcomas. Within our institution, three tumors with EGFR ITD were prospectively identified, all occurring in patients less than 1 year of age at diagnosis, including two renal tumors and one mediastinal soft tissue tumor. These three cases exhibited both cellular and mixed cellular and classic histology. All patients had no evidence of disease progression off therapy, despite incomplete resection. To extend our analysis and quantify the frequency of EGFR ITD in pediatric sarcomas, we retrospectively analyzed a cohort of tumors (n = 90) that were previously negative for clinical RT-PCR-based fusion testing. We identified EGFR ITD in three analyzed cases, all in patients less than 1 year of age (n = 18; 3/18, 17%). Here we expand the spectrum of tumors with EGFR ITD to congenital soft tissue tumors and report an unusual example of an EGFR ITD in a tumor with cellular congenital mesoblastic nephroma histology. We also highlight the importance of appropriate test selection and bioinformatic analysis for identification of this genomic alteration that is unexpectedly common in congenital and infantile spindle cell tumors., (© 2022 Wiley Periodicals LLC.)

The eighth Paediatric Strategy Forum focused on multi-targeted kinase inhibitors (mTKIs) in osteosarcoma and Ewing sarcoma. The development of curative, innovative products in these tumours is a high priority and addresses unmet needs in children, adolescents and adults. Despite clinical and investigational use of mTKIs, efficacy in patients with bone tumours has not been definitively demonstrated. Randomised studies, currently being planned or in progress, in front-line and relapse settings will inform the further development of this class of product. It is crucial that these are rapidly initiated to generate robust data to support international collaborative efforts. The experience to date has generally indicated that the safety profile of mTKIs as monotherapy, and in combination with chemotherapy or other targeted therapy, is consistent with that of adults and that toxicity is manageable. Increasing understanding of relevant predictive biomarkers and tumour biology is absolutely critical to further develop this class of products. Biospecimen samples for correlative studies and biomarker development should be shared, and a joint academic-industry consortium created. This would result in an integrated collection of serial tumour tissues and a systematic retrospective and prospective analyses of these samples to ensure robust assessment of biologic effect of mTKIs. To support access for children to benefit from these novel therapies, clinical trials should be designed with sufficient scientific rationale to support regulatory and payer requirements. To achieve this, early dialogue between academia, industry, regulators, and patient advocates is essential. Evaluating feasibility of combination strategies and then undertaking a randomised trial in the same protocol accelerates drug development. Where possible, clinical trials and development should include children, adolescents, and adults less than 40 years. To respond to emerging science, in approximately 12 months, a multi-stakeholder group will meet and review available data to determine future directions and priorities., Competing Interests: Conflcits of interest statement The authors declare the following financial interests/ personal relationships which may be considered as potential competing interests: FB is an employee and stockholder of Ipsen Pharma. JC is an employee of Bayer Healthcare Pharmaceuticals. MC has served as an advisor for Astra-Zeneca, Bayer, BMS, Pfizer, and Servier. SGD has received consulting fees from Amgen, Bayer, and Loxo Oncology and has received travel reimbursement from Roche and Salarius. EG is an employee of Oncoheroes Biosciences. AH is an employee of Blueprint Medicines. KJ has received consulting fees from Bayer and Ipsen and honoraria fromTakeda and Foundation Medicine. JK is an employee of Allarity Therapeutics. SK is an employee of HUTCHMED International Corporation. CO is an employee of Eisai GmbH. ADJP has consulted for Lilly, Norgine and Developmental Therapeutics Consortium Limited and been an advisor for Amgen. All remaining authors have declared no conflicts of interest., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Vascular anomalies are a heterogeneous group of disorders that are currently classified based on their clinical and histological characteristics. Over the past decade, there have been significant advances in molecular genetics that have led to identification of genetic alterations associated with vascular tumors, vascular malformations, and syndromes. Here, we describe known genetic alterations in vascular anomalies, discuss when and how to test, and examine how identification of causative genetic mutations provides for better management of these disorders through improved understanding of their pathogenesis and increasing use of targeted therapeutic agents in order to achieve better outcomes for our patients., (© 2021 Wiley Periodicals LLC.)

Background: We investigated whether surveillance imaging had an impact on post-relapse survival in patients with rhabdomyosarcoma (RMS). We hypothesized that relapse detected by imaging (group IM) would be associated with longer survival compared with relapse detected with a clinical sign or symptom (group SS)., Materials and Methods: We performed an observational multi-institutional study in 127 patients with relapsed RMS comparing overall survival (OS) after relapse using Kaplan-Meier and Cox proportional hazards analyses., Results: Relapse was detected in 60 (47%) group IM and 67 (53%) SS patients. Median follow-up in survivors was 4 years (range 1.0 to 16.7 y). Four-year OS rates were similar between group IM (28%, 95% confidence interval [CI]: 14%-40%) and SS (21%, 95% CI: 11%-31%) ( P =0.14). In multivariable analyses accounting for institution, age at diagnosis, time to relapse, risk group at diagnosis, and primary site, not receiving chemotherapy (hazard ratio [HR]: 6.8, 95% CI: 2.8-16.6), radiation (HR: 3, 95% CI: 1.7-5.3), or surgery (HR: 2.8, 95% CI: 1.6-4.8) after relapse were independently associated with poor OS., Conclusion: These results on whether surveillance imaging provides survival benefit in patients with relapsed RMS are inconclusive. Larger studies are needed to justify current surveillance recommendations. Chemotherapy, radiotherapy and surgery to treat recurrence prolong OS., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Natural killer (NK) cells possess an innate ability to recognize cancer and are key mediators of cytotoxic efficacy for anticancer antibodies. Recent advances in the ability to generate, qualify, and safely infuse NK cells have led to a wide variety of clinical trials in oncology. Although their efficacy is best established for liquid cancers, their potential application in solid cancers has received increased attention. Here, we provide general background across a disparate group of exemplary solid tumors for which there is evidence for an NK cell role, discuss NK cell recognition motifs specific to each and murine and human studies of each that are supportive of NK cell adoptive immunotherapy, and end with special considerations relevant to the solid tumor microenvironment., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: The objective of this study is to report disease outcomes and toxicity with the use of stereotactic body radiation therapy (SBRT) in the treatment of pediatric metastatic disease., Methods: All pediatric and adolescent young adult (AYA) patients' who received SBRT were included between the years 2000 and 2020. Study endpoints included local control (LC), progression-free survival (PFS), overall survival (OS), cumulative incidence (CI) of death or local failure and toxicity. The end points with respect to survival and LC were calculated using the Kaplan-Meier estimate. The cumulative incidence of local failure was calculated using death as a competing risk., Results: 16 patients with 36 lesions irradiated met inclusion criteria and formed the study cohort. The median OS and PFS for the entire cohort were 17 months and 15.7 months, respectively. The 1 year OS for the entire cohort was 75%. The 6- and 12 month local control was 85 and 78%, respectively. There were no local failures in irradiated lesions for patients who received a BED 10 ≥100 Gy. Patients who were treated with SBRT who had ≤5 metastatic lesions at first recurrence had a superior 1 year OS of 100  vs 50% for those with >5 lesions. One patient (6.3%) experienced a Grade 3 central nervous system toxicity., Conclusion: LC was excellent with SBRT delivered to metastatic disease, particularly for lesions receiving a BED 10 ≥100 Gy. High-grade toxicity was rare in our patient population. Patients with five or fewer metastatic sites have a significantly better OS compared to >5 sites., Advances in Knowledge: This study demonstrates that SBRT is safe and efficacious in the treatment of pediatric oligometastatic disease.

Syringocystadenocarcinoma papilliferum (SCACP) is a rare malignant neoplasm arising from adnexal tissues and is the malignant complement to the benign neoplasm syringocystadenoma papilliferum (SCAP). SCACP lesions appear as raised nodules or inflammatory plaques and can be associated with SCAP or nevus sebaceous. There have been fewer than 100 described cases of this neoplasm in the literature, and all previously published cases have been described in adults, with the majority occurring in the elderly. We present a case of an adolescent female with a syringocystadenocarcinoma papilliferum arising from a large thigh mass harboring an in-frame alteration in MAP 2 K 1 along with a brief review of the literature., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Jordan N. Halsey et al.)

Adolescent and young adult (AYA) patients with Ewing sarcoma have inferior survival compared with pediatric patients even when treated with similar regimens. Investigation into specific explanations is lacking. A retrospective chart review of Ewing sarcoma patients at a single institution was performed, and 104 patients were identified, 45 were 15 to 39 years of age (AYA cohort) and 59 younger than 15 years (pediatric cohort). AYA patients demonstrated more metastatic disease (50% vs. 24%, P=0.009), peripheral tumor location (64% vs. 41%, P=0.025), percentage of male patients (76% vs. 51%; P=0.010), and tumor size ≥5 cm (93% vs. 70%, P=0.016) than pediatric patients. Five-year overall survival was 77.7% and 53.0% and event-free survival was 68.7% and 40.6% for pediatric versus AYA, respectively. Similar rates of toxicity and chemotherapeutic dose adjustments were demonstrated. In this cohort, increased AYA patient mortality appears to be related to disease characteristics rather than treatment-related differences., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

We describe a rare pediatric case of a phalangeal giant cell tumor of bone with extensive bilateral lung metastases following curettage, wide resection, and amputation. Concurrent peripheral blood eosinophilia and pleural effusion with marked eosinophilia (47%) were present. To discover genetic changes driving tumor metastasis, genomic and transcriptome profiling of the metastatic lung mass as well as germline analysis were performed. Whole exome sequencing detected a histone H3F3A p.G35V missense mutation in tumor cells. RNA sequencing revealed overexpression of receptor activator of nuclear factor kappa-B ligand (RANKL). The patient is alive with no residual disease and uncompromised respiratory function 29 months after amputation of primary tumor and 19 months after surgical resection of his metastatic lung disease.

Infantile fibrosarcoma (IFS) is nearly universally driven by gene fusions involving the NTRK family. ETV6-NTRK3 fusions account for ∼85% of alterations; the remainder are attributed to NTRK-variant fusions. Rarely, other genomic aberrations have been described in association with tumors identified as IFS or IFS-like. We describe the utility of genomic characterization of an IFS-like tumor. We also describe the successful treatment combination of VAC (vincristine, actinomycin, cyclophosphamide) with tyrosine kinase inhibitor (TKI) maintenance in this entity. This patient presented at birth with a right facial mass, enlarging at 1 mo to 4.9 × 4.5 × 6.3 cm. Biopsy demonstrated hypercellular fascicles of spindle cells with patchy positivity for smooth muscle actin (SMA) and negativity for S100, desmin, myogenin, and MyoD1. Targeted RNA sequencing identified a novel RBPMS-MET fusion with confirmed absence of ETV6-NTRK3 , and the patient was diagnosed with an IFS-like tumor. A positron emission tomography (PET) scan was negative for metastatic disease. VAC was given for a duration of 10 mo. Resection at 13 mo of age demonstrated positive margins. Cabozantinib, a MET-targeting TKI, was initiated. The patient tolerated cabozantinib well and has no evidence of disease at 24 mo of age. We describe a novel RBPMS-MET driver fusion in association with a locally aggressive IFS-like tumor. MET functions as an oncogene and, when associated with the RNA binding protein RBPMS, forms an in-frame fusion product that retains the MET kinase domain. This fusion is associated with aberrant cell signaling pathway expression and subsequent malignancy. We describe treatment with cabozantinib in a patient with an IFS-like neoplasm., (© 2020 Gupta et al.; Published by Cold Spring Harbor Laboratory Press.)

Vincristine-induced constipation is a common side effect in pediatric oncology patients. We report the case of an infant with histologic diagnosis of infantile fibrosarcoma who developed significant constipation because of ongoing vincristine administration. She was treated with osteopathic manipulative treatment and had significant improvement in symptoms. She was able to stop her home lactulose bowel regimen without signs or symptoms of constipation. This case demonstrates the benefit of osteopathic manipulative treatment for chemotherapy-induced constipation as an effective and simple supportive care option without added adverse events.

Background: The combination of gemcitabine and docetaxel is often used to treat patients with recurrent sarcoma. Nab-paclitaxel is a taxane modified to improve drug exposure and increase intratumoral accumulation and, in combination with gemcitabine, is standard therapy for pancreatic cancer. Applying the dosages and schedule used for pancreatic cancer, we performed a phase II trial to assess the response rate of gemcitabine and nab-paclitaxel in patients with relapsed Ewing sarcoma., Procedure: Using a Simon's two-stage design to identify a response rate of ≥ 35%, patients received nab-paclitaxel 125 mg/m 2 followed by gemcitabine 1000 mg/m 2 i.v. on days 1, 8, and 15 of four-week cycles. Immunohistochemical analysis of archival tissue was performed to identify possible biomarkers of response., Results: Eleven patients from four institutions enrolled, with a median age of 22 years (range, 14-27). Patients were heavily pretreated (median 3 prior regimens, range, 1-7). Thirty-five cycles were administered (median 2, range, 1-8). Accrual was stopped after 11 patients, due to only one confirmed partial response. Two other patients had partial responses after two cycles, but withdrew because of adverse effects or progression before confirmation of continued response. The predominant toxicity was myelosuppression, and four (36%) patients were removed due to hematologic toxicity despite pegfilgrastim and dose reductions. Expression of secreted protein, acidic and rich in cysteine (SPARC) and CAV-1 in archival tumors was not predictive of clinical benefit in this small cohort of patients., Conclusions: In patients with heavily pretreated Ewing sarcoma, the confirmed response rate of 9% was similar to multi-institutional studies of gemcitabine and docetaxel., (© 2020 Wiley Periodicals, Inc.)

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare and aggressive malignancy. Though the molecular underpinnings of this cancer have been largely unexplored, recurrent chromosomal breakpoints affecting a noncoding region on chr19q13, which includes the chromosome 19 microRNA cluster (C19MC), have been reported in several cases. We performed comprehensive molecular profiling on samples from 14 patients diagnosed with UESL. Congruent with prior reports, we identified structural variants in chr19q13 in 10 of 13 evaluable tumors. From whole transcriptome sequencing, we observed striking expressional activity of the entire C19MC region. Concordantly, in 7 of 7 samples undergoing miRNAseq, we observed hyperexpression of the miRNAs within this cluster to levels >100 fold compared to matched normal tissue or a non-C19MC amplified cancer cell line. Concurrent TP53 mutation or copy number loss was identified in all evaluable tumors with evidence of C19MC overexpression. We find that C19MC miRNAs exhibit significant negative correlation to TP53 regulatory miRNAs and K-Ras regulatory miRNAs. Using RNA-seq we identified that pathways relevant to cellular differentiation as well as mRNA translation machinery are transcriptionally enriched in UESL. In summary, utilizing a combination of next-generation sequencing and high-density arrays we identify the combination of C19MC hyperexpression via chromosomal structural event with TP53 mutation or loss as highly recurrent genomic features of UESL., Competing Interests: The authors have declared that no competing interests exist.

Natural killer (NK) cells are lymphocytes of the innate immune system that have the ability to recognize malignant cells through balanced recognition of cell-surface indicators of stress and danger. Once activated through such recognition, NK cells release cytokines and induce target cell lysis through multiple mechanisms. NK cells are increasingly recognized for their role in controlling tumor progression and metastasis and as important mediators of immunotherapeutic modalities such as cytokines, antibodies, immunomodulating drugs, and stem cell transplantation. Recent advances in manipulating NK cell number, function, and genetic modification have caused renewed interest in their potential for adoptive immunotherapies, which are actively being tested in clinical trials. Here, we summarize the evidence for NK cell recognition of osteosarcoma, discuss immune therapies that are directly or indirectly dependent on NK cell function, and describe potential approaches for manipulating NK cell number and function to enhance therapy against osteosarcoma.

Paraspinal tumors with benign histology in the absence of trauma rarely arise in children. Treatment of such benign tumors, in contrast to malignancies, generally consists of surgical resection of the lesion with confirmation of histology via pathologic evaluation. We present a pediatric case of an atraumatic paraspinal mass with a histologic diagnosis of aneurysmal bone cyst, and USP6 gene rearrangement supporting the histologic diagnosis. The patient underwent gross total resection of the paraspinal lesion with no additional intervention. We highlight the differential diagnosis of paraspinal tumors in children and key features that led to the diagnosis in this patient.

Background: The combination of vincristine, irinotecan, and temozolomide (VIT) is often used to treat children and adolescents with relapsed rhabdomyosarcoma (RMS); however, the outcome of these patients has not been previously described., Procedures: We sought to determine the response rate (RR) and progression-free survival (PFS) for patients with relapsed RMS treated with VIT by retrospective review of patients treated at five tertiary care hospitals. Prior treatment with irinotecan was permitted., Results: Among 19 patients with a median age of 8 years (range 2-17 years), 12 (63%) were males and 12 (63%) had embryonal histology. Median time to relapse from initial diagnosis was 16 months (range 2.8-45 months). VIT was used as first, second, third, or fourth line of therapy in four (21%), seven (37%), six (32%), and two (10%) patients, respectively. Four patients received VIT as adjuvant therapy following radiation and/or surgery. Therefore, among 15 evaluable patients, the best response to VIT was 0 (complete response, CR), 0 (partial response, PR), 4 (stable disease, SD), and 11 (progressive disease, PD) for an overall clinical benefit rate (CR + PR + SD) of 26.7% (95% CI: 7.8-55.1%). After a median follow-up of 8 months, 2 (10%) patients were alive without disease, 3 (16%) were alive with disease, and 14 (74%) patients died of PD. PFS at 3 months was 23% (95% CI: 5.7-46.7%)., Conclusions: VIT therapy in combination with adequate local control is associated with some disease control in patients with first relapse RMS and may be another reasonable option to offer patients as salvage therapy., (© 2017 Wiley Periodicals, Inc.)

Therapy-related thrombocytopenia (TRT), due to chemotherapy and/or radiation therapy, is common with pediatric cancer treatments, and it can result in dose reductions and therapy delays. Romiplostim, a thrombopoietin mimetic, is efficacious as a second-line treatment for immune thrombocytopenia in children and for TRT in adult cancer patients. However, there are no data for its use for TRT in children. We report a case series of five children treated for solid tumors where romiplostim was used without adverse effects to successfully resolve and prevent therapy-limiting refractory TRT. Prospective studies on this use of romiplostim are warranted., (© 2017 Wiley Periodicals, Inc.)

Solid tumors can often be hypoxic in regions, and cancer cells can respond to hypoxia with an increase in proliferation and a decrease in apoptosis, leading to a net increase in viable cell numbers. We have recently found that in an osteosarcoma cell line, hypoxia-induced proliferation depends on arginase II induction. Epidermal growth factor receptor (EGFR) has been shown to mediate the hypoxia-induced cellular proliferation in some cancer cell lines. We hypothesized that hypoxia-induced proliferation of HeLa cells would depend on arginase II induction and that this induction of arginase II would occur through EGFR activation. Exposure of HeLa cells to hypoxia resulted in an upregulation of arginase II mRNA and protein levels, with no effect on arginase I expression. Hypoxia also resulted in significantly greater viable cell numbers than did normoxia. The hypoxia-induced increase in viable cell numbers was prevented by either a small molecule inhibitor of arginase or siRNA targeting arginase II Overexpression of arginase II resulted in an increase in viable cell numbers both in normoxia and hypoxia. Hypoxia caused a substantial induction of both epidermal growth factor (EGF) and EGFR Preventing hypoxia-induced EGFR expression using siRNA abolished hypoxia-induced arginase II expression and the increase in viable cell numbers. Treatment with EGF in normoxia not only induced arginase II expression but also resulted in an increase in viable cell numbers. Blocking EGF interactions with EGFR using either an EGF neutralizing antibody or an EGFR antibody prevented the hypoxia-induced increase in viable cell numbers. These results demonstrate an EGF/EGFR/arginase II pathway that is necessary for hypoxic proliferation in HeLa cells., (© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

Soft tissue sarcoma constitutes 8% of all tumors in adolescent and young adults (AYA), with rhabdomyosarcoma (RMS) accounting for 5.2% to 6.5% of the soft tissue sarcoma total within this group. AYAs have a higher propensity for metastasis and inferior outcomes. Metastases to the breast have been reported in ∼3% to 6% of RMS cases. A review of our hospital's tumor registry identified cases of RMS diagnosed between January 1, 2004 and December 31, 2013. A total of 46 patients with RMS were identified, having a mean age of 12.5 years (range, 1 to 49 y). There were 26 males (57%) and 20 females (43%). Eighteen patients (39%) were AYAs, including 10 women. Four patients (8.7%) were identified with breast involvement, all of whom were AYA females. Treatment modalities included chemotherapy, surgical resection, and radiation. One patient is a long-term survivor. Although RMS is uncommon in AYAs, breast involvement occurs almost exclusively in AYA women and is associated with alveolar histology, metastatic disease, and poor outcomes. In total, 4/10 of all AYA females had breast involvement. Routine examination or imaging of the breasts in AYAs with RMS is not currently standard practice at diagnosis or follow-up, but this analysis suggests it should be considered in female AYA patients.

Pediatric soft tissue sarcomas of the oral/maxillofacial region are rare neoplasms that present significant difficulty with respect to treatment and local control measures. We report four cases of pediatric oral/maxillofacial soft tissue sarcomas from our tertiary care pediatric hospital and emphasize the rarity of these malignancies and the challenges encountered in treating these lesions, and suggest areas for further research. We conclude that multimodal therapy and interdisciplinary cooperation are paramount to successful management of these lesions.

Background/aims: Despite significant advancements in the diagnosis and treatment of osteosarcoma, the overall survival has remained relatively unchanged for over two decades. Hypoxic conditions have been demonstrated in solid tumors and are associated with increased cell proliferation and angiogenesis. L-arginine metabolism by arginase produces L-ornithine, the precursor for polyamine and proline synthesis required for cellular proliferation. We hypothesized that hypoxia would increase cellular proliferation via arginase induction in human osteosarcoma cell lines., Methods: We utilized a variety of approaches to examine the role of arginase II in hypoxic (1% O2, 5% CO2) cellular proliferation., Results: Arginase II mRNA and protein levels were significantly increased in osteosarcoma cells exposed to hypoxia for 48 hours. There were twice as many viable cells following 48 hours of hypoxia than following 48 hours of normoxia (21% O2, 5% CO2). The addition of difluoromethylornithine (DFMO), a putative arginase inhibitor, prevented hypoxia-induced proliferation. Transfection of small interfering RNAs (siRNA) targeting arginase II resulted in knockdown of arginase II protein levels and prevented hypoxia-induced cellular proliferation., Conclusions: These data support our hypothesis that hypoxia increases proliferation of osteosarcoma cells in an arginase II-dependent manner. We speculate that arginase II may represent a therapeutic target in osteosarcoma., (© 2016 The Author(s) Published by S. Karger AG, Basel.)

Background: Pediatric venous thromboembolism (VTE) is an increasingly common problem. We hypothesized that VTE occurs most commonly in tertiary care settings and that the pattern of associated illnesses may have changed from earlier reports., Methods: The Kids' Inpatient Database 2006 was utilized to identify children ≤ 18 years old with in-hospital VTE. Children were identified by the presence of thrombosis specific ICD-9-CM diagnosis or procedure codes. Remaining ICD-9-CM codes were utilized to categorize patients by acute or chronic illness. The incidence of in-hospital VTE by hospital type, age, gender, race, and disposition were estimated., Results: Over 4,500 children met the inclusion criteria (188/100,000 discharges). Most VTE discharges (67.5%) were from children's hospitals (RR 5.09; 95% CI 4.76; 5.44). Underlying chronic illnesses were associated with most VTE (76.2%), most commonly: cardiovascular (18.4%), malignancy (15.7%), and neuromuscular disease (9.9%). VTE not associated with chronic illness were most often idiopathic (12.6%), followed by infections (9.5%), and trauma (9.1%). The greatest proportions of children with VTE were infants (23.1%) and adolescents (37.8%). However, when standardized against the entire database of discharges, infants were least likely to develop VTE (RR 0.48; 95% CI 0.43; 0.52), while adolescents were at highest risk (RR 1.89; 95% CI 1.73; 2.07). Hospitalizations ending with death were more likely to include VTE (RR 6.16; 95% CI 5.32; 7.13)., Conclusions: Pediatric VTE is most commonly seen in tertiary care. Adolescents are at greatest risk to develop in-hospital VTE. Patients whose hospitalization ended with death are at much greater risk to develop VTE., (Copyright © 2011 Wiley Periodicals, Inc.)

Severe congenital neutropenia is an autosomal recessive disorder characterized by maturation arrest at the promyelocyte/myelocyte phase in the bone marrow, absolute neutrophil count <0.5 × 10(9) /L and recurrent bacterial infections. Homozygous mutations of either HAX-1 or ELA-2 have been described. We report the case of a premature male infant with congenital neutropenia, associated with multiple infections, refractory to treatment with granulocyte colony stimulating factor who subsequently underwent matched sibling donor stem-cell transplant. He was found to be heterozygous for the M1V variant of the ELA-2 gene that we postulate to be causative for his severe neutropenia, (Copyright © 2011 Wiley-Liss, Inc.)

Of the cases of non-Hodgkin lymphoma (NHL) diagnosed in children and adolescents, 10% comprise a diverse mixture of unusual B-cell or T-cell disease, some types of which are more commonly seen in adults. Understanding of these rare types of NHL comes from small pediatric case series or the adult literature. Some rare pediatric NHL is similar to adult NHL, but other types have different molecular and cytogenetic characteristics. It is important to improve understanding and treatment of these rare pediatric NHLs through international collaborative efforts.