Loss of ALK hotspot mutations in relapsed neuroblastoma.

ALK is the most commonly mutated oncogene in neuroblastoma with increased mutation frequency reported at relapse. Here we report the loss of an ALK mutation in two patients at relapse and a paired neuroblastoma cell line at relapse. ALK detection methods including Sanger sequencing, targeted next-generation sequencing and a new ALK Agena MassARRAY technique were used to detect common hotspot ALK variants in tumors at diagnosis and relapse from two high-risk neuroblastoma patients. Copy number analysis including single nucleotide polymorphism array and array comparative genomic hybridization confirmed adequate tumor cell content in DNA used for mutation testing. Case 1 presented with an ALK F1174L mutation at diagnosis with a variant allele frequency (VAF) ranging between 23.5% and 28.5%, but the mutation was undetectable at relapse. Case 2 presented with an ALK R1257Q mutation at diagnosis (VAF = 39%-47.4%) which decreased to <0.01% at relapse. Segmental chromosomal aberrations were maintained between diagnosis and relapse confirming sufficient tumor cell content for mutation detection. The diagnostic SKNBE1n cell line harbors an ALK F1174S mutation, which was lost in the relapsed SKNBE2c cell line. To our knowledge, these are the first reported cases of loss of ALK mutations at relapse in neuroblastoma in the absence of ALK inhibitor therapy, reflecting intra-tumoral spatial and temporal heterogeneity. As ALK inhibitors are increasingly used in the treatment of refractory/relapsed neuroblastoma, our study highlights the importance of confirming whether an ALK mutation detected at diagnosis is still present in clones leading to relapse.

Macrocycle Dynamics in a Branched [8]Catenane Controlled by Three Different Stimuli in Three Different Regions.

A branched [8]catenane from an efficient one-pot synthesis (72 % HPLC yield, 59 % isolated yield) featuring the simultaneous use of three kinds of templates and cucurbit[6]uril-mediated azide-alkyne cycloaddition (CBAAC) for ring-closing is reported. Design and assembly of the [8]catenane precursors are unexpectedly complex that can involve cooperating, competing and non-influencing interactions. Due to the branched structure, dynamics of the [8]catenane can be modulated in different extent by rigidifying/loosening the mechanical bonds at different regions by using solvent polarity, acid-base and metal ions as the stimuli. This work not only highlights the importance of understanding the delicate interplay of the weak and non-obvious supramolecular interactions in the synthesis of high-order [n]catenane, but also demonstrates a complex control of dynamics and flexibility for exploiting [n]catenanes applications.

Surveillance for subsequent neoplasms of the CNS for childhood, adolescent, and young adult cancer survivors: a systematic review and recommendations from the International Late Effects of Childhood Cancer Guideline Harmonization Group.

Exposure to cranial radiotherapy is associated with an increased risk of subsequent CNS neoplasms among childhood, adolescent, and young adult (CAYA) cancer survivors. Surveillance for subsequent neoplasms can translate into early diagnoses and interventions that could improve cancer survivors' health and quality of life. The practice guideline presented here by the International Late Effects of Childhood Cancer Guideline Harmonization Group was developed with an evidence-based method that entailed the gathering and appraisal of published evidence associated with subsequent CNS neoplasms among CAYA cancer survivors. The preparation of these guidelines showed a paucity of high-quality evidence and highlighted the need for additional research to inform survivorship care. The recommendations are based on careful consideration of the evidence supporting the benefits, risks, and harms of the surveillance interventions, clinical judgment regarding individual patient circumstances, and the need to maintain flexibility of application across different health-care systems. Currently, there is insufficient evidence to establish whether early detection of subsequent CNS neoplasms reduces morbidity and mortality, and therefore no recommendation can be formulated for or against routine MRI surveillance. The decision to start surveillance should be made by the CAYA cancer survivor and health-care provider after careful consideration of the potential harms and benefits of surveillance for CNS neoplasms, including meningioma.

Radial Hetero[5]catenanes: Peripheral Isomer Sequences of the Interlocked Macrocycles.

A pair of radial [5]catenanes, with either an isomeric cyclic -AABB- or -ABAB- type sequence of the interlocked ß-cyclodextrin (ß-CD) and cucurbit[6]uril (CB[6]) units, has been efficiently synthesized. Because of a marked difference in the binding strength and interlocking sequence of the peripheral macrocycles, interesting sequence-dependent properties, characteristic of mechanically bonded macrocycles, were realized. Variable-temperature 1 H NMR studies showed that the -ABAB- isomer has a more independent ß-CD dynamic, whereas the ß-CD motions in the -AABB- isomer are coupled. Dynamics of the pH-insensitive ß-CD can also be further modulated upon base-triggered mobilization of the CB[6]. These unique properties of the mechanical bond expressed in a sequence-specific fashion and the transmission of the control on the macrocycle dynamics from one interlocked component to another, highlight the potential of similar complex hetero[n]catenanes in the design of advanced, multicomponent molecular machines.

Respiratory mortality of childhood, adolescent and young adult cancer survivors.

BACKGROUND: Exposure to radiation and/or chemotherapy during cancer treatment can compromise respiratory function. We investigated the risk of long-term respiratory mortality among 5-year cancer survivors diagnosed before age 40 years using the British Childhood Cancer Survivor Study (BCCSS) and Teenage and Young Adult Cancer Survivor Study (TYACSS). METHODS: The BCCSS comprises 34 489 cancer survivors diagnosed before 15 years from 1940 to 2006 in Great Britain. The TYACSS includes 200 945 cancer survivors diagnosed between 15 years and 39 years from 1971 to 2006 in England and Wales. Standardised mortality ratios and absolute excess risks were used. FINDINGS: Overall, 164 and 1079 respiratory deaths were observed in the BCCSS and TYACSS cohorts respectively, which was 6.8 (95% CI 5.8 to 7.9) and 1.7 (95% CI 1.6 to 1.8) times that expected, but the risks varied substantially by type of respiratory death. Greatest excess numbers of deaths were experienced after central nervous system (CNS) tumours in the BCCSS and after lung cancer, leukaemia, head and neck cancer and CNS tumours in the TYACSS. The excess number of respiratory deaths increased with increasing attained age, with seven (95% CI 2.4 to 11.3) excess deaths observed among those aged 50+ years in the BCCSS and three (95% CI 1.4 to 4.2) excess deaths observed among those aged 60+ years in the TYACSS. It was reassuring to see a decline in the excess number of respiratory deaths among those diagnosed more recently in both cohorts. CONCLUSIONS: Prior to this study, there was almost nothing known about the risks of respiratory death after cancer diagnosed in young adulthood, and this study addresses this gap. These new findings will be useful for both survivors and those involved in their clinical management and follow-up.

Strategies To Assemble Catenanes with Multiple Interlocked Macrocycles.

As a major class of mechanically interlocked molecules, not only are catenanes topologically intriguing targets that challenge the chemical synthesis to the efficient formation of mechanical bonds, but also the mechanical properties arising from the topology offer unique and attractive features for the development of novel functional molecular materials. Despite advancements in templated methods for different types of interlocked architectures, [ n]catenane possessing multiple numbers of interlocked macrocycles still remains a difficult synthetic target with very few reported examples. If the unique mechanical properties of catenanes are to be fully exploited, reliable, controllable, and efficient strategies for accessing [ n]catenanes will be necessary. In this Viewpoint, challenges, considerations, and strategies to [ n]catenanes are discussed.

Efficient catenane synthesis by cucurbit[6]uril-mediated azide-alkyne cycloaddition.

We report here the efficient synthesis of a series of [3]catenanes featuring the use of cucurbit[6]uril to simultaneously mediate the mechanical and covalent bond formations. By coupling the mechanical interlocking with covalent macrocyclization, formation of topological isomers is eliminated and the [3]catenanes are formed exclusively in good yields. The efficient access to these [3]catenanes and the presence of other recognition units render them promising building blocks for the construction of other high-order interlocked structures.

PARC: a phase I/II study evaluating the safety and activity of pegylated recombinant human arginase BCT-100 in relapsed/refractory cancers of children and young adults.

Background: The survival for many children with relapsed/refractory cancers remains poor despite advances in therapies. Arginine metabolism plays a key role in the pathophysiology of a number of pediatric cancers. We report the first in child study of a recombinant human arginase, BCT-100, in children with relapsed/refractory hematological, solid or CNS cancers. Procedure: PARC was a single arm, Phase I/II, international, open label study. BCT-100 was given intravenously over one hour at weekly intervals. The Phase I section utilized a modified 3 + 3 design where escalation/de-escalation was based on both the safety profile and the complete depletion of arginine (defined as adequate arginine depletion; AAD <8µM arginine in the blood after 4 doses of BCT-100). The Phase II section was designed to further evaluate the clinical activity of BCT-100 at the pediatric RP2D determined in the Phase I section, by recruitment of patients with pediatric cancers into 4 individual groups. A primary evaluation of response was conducted at eight weeks with patients continuing to receive treatment until disease progression or unacceptable toxicity. Results: 49 children were recruited globally. The Phase I cohort of the trial established the Recommended Phase II Dose of 1600U/kg iv weekly in children, matching that of adults. BCT-100 was very well tolerated. No responses defined as a CR, CRi or PR were seen in any cohort within the defined 8 week primary evaluation period. However a number of these relapsed/refractory patients experienced prolonged radiological SD. Conclusion: Arginine depletion is a clinically safe and achievable strategy in children with cancer. The RP2D of BCT-100 in children with relapsed/refractory cancers is established at 1600U/kg intravenously weekly and can lead to sustained disease stability in this hard to treat population. Clinical trial registration: EudraCT, 2017-002762-44; ISRCTN, 21727048; and ClinicalTrials.gov, NCT03455140.

Recommendations for surveillance of pulmonary dysfunction among childhood, adolescent, and young adult cancer survivors: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group.

Childhood, adolescent, and young adult (CAYA) cancer survivors are at risk of pulmonary dysfunction. Current follow-up care guidelines are discordant. Therefore, the International Late Effects of Childhood Cancer Guideline Harmonization Group established and convened a panel of 33 experts to develop evidence-based surveillance guidelines. We critically reviewed available evidence regarding risk factors for pulmonary dysfunction, types of pulmonary function testing, and timings of surveillance, then we formulated our recommendations. We recommend that CAYA cancer survivors and healthcare providers are aware of reduced pulmonary function risks and pay vigilant attention to potential symptoms of pulmonary dysfunction, especially among survivors treated with allogeneic haematopoietic stem cell transplantation, thoracic radiotherapy, and thoracic surgery. Based on existing limited evidence and current lack of interventions, our panel recommends pulmonary function testing only for symptomatic survivors. Since scarce existing evidence informs our recommendation, we highlight the need for prospective collaborative studies to address pulmonary function knowledge gaps among CAYA cancer survivors.

Detection of Circulating and Disseminated Neuroblastoma Cells Using the ImageStream Flow Cytometer for Use as Predictive and Pharmacodynamic Biomarkers.

PURPOSE: Circulating tumor cells (CTCs) serve as noninvasive tumor biomarkers in many types of cancer. Our aim was to detect CTCs from patients with neuroblastoma for use as predictive and pharmacodynamic biomarkers. EXPERIMENTAL DESIGN: We collected matched blood and bone marrow samples from 40 patients with neuroblastoma to detect GD2 +/CD45- neuroblastoma CTCs from blood and disseminated tumor cells (DTCs) from bone marrow using the Imagestream Imaging flow cytometer (ISx). In six cases, circulating free DNA (cfDNA) extracted from plasma isolated from the CTC sample was analyzed by high-density single-nucleotide polymorphism (SNP) arrays. RESULTS: CTCs were detected in 26 of 42 blood samples (1-264/mL) and DTCs in 25 of 35 bone marrow samples (57-291,544/mL). Higher numbers of CTCs in patients with newly diagnosed, high-risk neuroblastoma correlated with failure to obtain a complete bone marrow (BM) metastatic response after induction chemotherapy (P < 0.01). Ex vivo Nutlin-3 (MDM2 inhibitor) treatment of blood and BM increased p53 and p21 expression in CTCs and DTCs compared with DMSO controls. In five of six cases, cfDNA analyzed by SNP arrays revealed copy number abnormalities associated with neuroblastoma. CONCLUSIONS: This is the first study to show that CTCs and DTCs are detectable in neuroblastoma using the ISx, with concurrently extracted cfDNA used for copy number profiling, and may be useful as pharmacodynamic biomarkers in early-phase clinical trials. Further investigation is required to determine whether CTC numbers are predictive biomarkers of BM response to first-line induction chemotherapy.

Molecular Links and Knots from Naphthalenediimide: A Balance of Weak Interactions.

Owing to its unique structural, electronic, spectroscopic, and redox properties, naphthalenediimide (NDI) is a versatile building block for the construction of a wide variety of supramolecular assemblies with diverse structures, properties, and functions. In this Minireview, the synthesis of topologically nontrivial molecular links and knots based on naphthalenediimide-derived building blocks will be discussed. In particular, the supramolecular forces that contribute to the formation of these molecular links and knots and their interactions will be discussed.

Control over the macrocyclisation pathway and product topology in a copper-templated catenane synthesis.

We report here that the product topology in a copper-templated catenane synthesis can be controlled by favouring a particular macrocyclisation pathway, offering an additional strategy for improving the efficiency of catenane formation. A linear [4]catenane was obtained by non-covalently modifying a flexible building block that favours the intra-ligand cyclisation.

Chemosensitivity in pediatric dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a rare tumor of fibrohistiocytic spectrum and uncommonly presents in infancy and childhood. The standard treatment is wide-margin surgical excision, but this is difficult to achieve in large tumors and may result in unacceptable cosmetic, structural, and functional consequences. The authors describe a child with recurring DFSP who, after extensive surgery, responded to treatment with vinblastine and oral methotrexate. This is the first reported case in literature of a chemotherapeutic response in pediatric DFSP.