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BACKGROUND: Precision medicine is projected to become integral to childhood cancer care. As such, it is essential to support families to understand what precision medicine entails. METHODS: A total of 182 parents and 23 adolescent patients participating in Precision Medicine for Children with Cancer (PRISM), an Australian precision medicine clinical trial for high-risk childhood cancer, completed questionnaires after study enrollment (time 0 [T0]). Of the parents, 108 completed a questionnaire and 45 completed an interview following return of precision medicine results (time 1 [T1]). We analyzed the mixed-methods data comprising measures exploring families' perceptions and understanding of PRISM's participant information sheet and consent form (PISCF), and factors associated with understanding. RESULTS: Most parents were satisfied with the PISCF, rating it as at least "somewhat" clearly presented (n = 160/175; 91%) and informative (n = 158/175; 90%). Many suggested improvements including the use of clearer language and a more visually engaging format. Parents' actual understanding of precision medicine was low on average, but scores improved between T0 and T1 (55.8/100-60.0/100; p = .012). Parents from culturally and/or linguistically diverse backgrounds (n = 42/177; 25%) had lower actual understanding scores than those from a Western/European background whose first language was English (p = .010). There was little correlation between parents' perceived and actual understanding scores (p = .794; Pearson correlation -0.020; 95% CI, -0.169 to 0.116). Most adolescent patients read the PISCF either "briefly" or "not at all" (70%) and had a perceived understanding score of 63.6/100 on average. CONCLUSIONS: Our study revealed gaps in families' understanding of childhood cancer precision medicine. We highlighted areas for potential intervention such as through targeted information resources. PLAIN LANGUAGE SUMMARY: Precision medicine is projected to become part of the standard of care for children with cancer. Precision medicine aims to give the right treatment to the right patient and involves several complex techniques, many of which may be challenging to understand. Our study analyzed questionnaire and interview data from parents and adolescent patients enrolled in an Australian precision medicine trial. Findings revealed gaps in families' understanding of childhood cancer precision medicine. Drawing on parents' suggestions and the literature, we make brief recommendations about improving information provision to families, such as through targeted information resources.
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Neoplasias , Medicina de Precisão , Humanos , Criança , Adolescente , Neoplasias/terapia , Austrália , Pais , IdiomaRESUMO
Melanoma of the skin is a common cancer only in Europeans, whereas it arises in internal body surfaces (mucosal sites) and on the hands and feet (acral sites) in people throughout the world. Here we report analysis of whole-genome sequences from cutaneous, acral and mucosal subtypes of melanoma. The heavily mutated landscape of coding and non-coding mutations in cutaneous melanoma resolved novel signatures of mutagenesis attributable to ultraviolet radiation. However, acral and mucosal melanomas were dominated by structural changes and mutation signatures of unknown aetiology, not previously identified in melanoma. The number of genes affected by recurrent mutations disrupting non-coding sequences was similar to that affected by recurrent mutations to coding sequences. Significantly mutated genes included BRAF, CDKN2A, NRAS and TP53 in cutaneous melanoma, BRAF, NRAS and NF1 in acral melanoma and SF3B1 in mucosal melanoma. Mutations affecting the TERT promoter were the most frequent of all; however, neither they nor ATRX mutations, which correlate with alternative telomere lengthening, were associated with greater telomere length. Most melanomas had potentially actionable mutations, most in components of the mitogen-activated protein kinase and phosphoinositol kinase pathways. The whole-genome mutation landscape of melanoma reveals diverse carcinogenic processes across its subtypes, some unrelated to sun exposure, and extends potential involvement of the non-coding genome in its pathogenesis.
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Genoma Humano/genética , Melanoma/genética , Mutação/genética , DNA Helicases/genética , GTP Fosfo-Hidrolases/genética , Genes p16 , Humanos , Melanoma/classificação , Proteínas de Membrana/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Neurofibromatose 1/genética , Proteínas Nucleares/genética , Fosfoproteínas/genética , Proteínas Proto-Oncogênicas B-raf/genética , Fatores de Processamento de RNA/genética , Transdução de Sinais/efeitos dos fármacos , Telomerase/genética , Telômero/genética , Proteína Supressora de Tumor p53/genética , Raios Ultravioleta/efeitos adversos , Proteína Nuclear Ligada ao XRESUMO
The replicative immortality of human cancer cells is achieved by activation of a telomere maintenance mechanism (TMM). To achieve this, cancer cells utilise either the enzyme telomerase, or the Alternative Lengthening of Telomeres (ALT) pathway. These distinct molecular pathways are incompletely understood with respect to activation and propagation, as well as their associations with clinical outcomes. We have identified significant differences in the telomere repeat composition of tumours that use ALT compared to tumours that do not. We then employed a machine learning approach to stratify tumours according to telomere repeat content with an accuracy of 91.6%. Importantly, this classification approach is applicable across all tumour types. Analysis of pathway mutations that were under-represented in ALT tumours, across 1,075 tumour samples, revealed that the autophagy, cell cycle control of chromosomal replication, and transcriptional regulatory network in embryonic stem cells pathways are involved in the survival of ALT tumours. Overall, our approach demonstrates that telomere sequence content can be used to stratify ALT activity in cancers, and begin to define the molecular pathways involved in ALT activation.
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Biologia Computacional/métodos , Neoplasias/genética , Homeostase do Telômero/genética , Telômero/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Correpressoras , Bases de Dados Genéticas , Feminino , Humanos , Aprendizado de Máquina , Melanoma/genética , Melanoma/mortalidade , Chaperonas Moleculares , Mutação , Neoplasias/mortalidade , Proteínas Nucleares/genética , Regiões Promotoras Genéticas , Análise de Sobrevida , Telomerase/genética , Sequenciamento do Exoma , Proteína Nuclear Ligada ao X/genéticaRESUMO
Genes encoding TRK are oncogenic drivers in multiple tumour types including infantile fibrosarcoma, papillary thyroid cancer and high-grade gliomas (HGG). TRK fusions have a critical role in tumourigenesis in 40% of infant HGG. Here we report the first case of a TRK fusion-driven HGG treated with larotrectinib-the first selective pan-TRK inhibitor in clinical development. This 3-year-old girl had failed multiple therapies including chemotherapy and radiotherapy. Tumour profiling confirmed an ETV6-NTRK3 fusion. Treatment with larotrectinib led to rapid clinical improvement with near total resolution of primary and metastatic lesions on MRI imaging. This is the first report of a TRK fusion glioma successfully treated with a TRK inhibitor.
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Neoplasias Encefálicas/tratamento farmacológico , Glioma/tratamento farmacológico , Pirazóis/administração & dosagem , Pirimidinas/administração & dosagem , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Pré-Escolar , Feminino , Glioma/diagnóstico por imagem , Glioma/genética , Glioma/patologia , Humanos , Imageamento por Ressonância Magnética , Gradação de Tumores , Proteínas de Fusão Oncogênica/genética , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Resultado do Tratamento , Sequenciamento Completo do GenomaRESUMO
Telomeres are terminal repetitive DNA sequences on chromosomes, and are considered to comprise almost exclusively hexameric TTAGGG repeats. We have evaluated telomere sequence content in human cells using whole-genome sequencing followed by telomere read extraction in a panel of mortal cell strains and immortal cell lines. We identified a wide range of telomere variant repeats in human cells, and found evidence that variant repeats are generated by mechanistically distinct processes during telomerase- and ALT-mediated telomere lengthening. Telomerase-mediated telomere extension resulted in biased repeat synthesis of variant repeats that differed from the canonical sequence at positions 1 and 3, but not at positions 2, 4, 5 or 6. This indicates that telomerase is most likely an error-prone reverse transcriptase that misincorporates nucleotides at specific positions on the telomerase RNA template. In contrast, cell lines that use the ALT pathway contained a large range of variant repeats that varied greatly between lines. This is consistent with variant repeats spreading from proximal telomeric regions throughout telomeres in a stochastic manner by recombination-mediated templating of DNA synthesis. The presence of unexpectedly large numbers of variant repeats in cells utilizing either telomere maintenance mechanism suggests a conserved role for variant sequences at human telomeres.
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Homeostase do Telômero , Telômero/química , Linhagem Celular , Variação Genética , Humanos , Sequências Repetitivas de Ácido Nucleico , Análise de Sequência de DNA , Telomerase/metabolismoRESUMO
Alternative lengthening of telomeres (ALT) is one of the two known telomere length maintenance mechanisms that are essential for the unlimited proliferation potential of cancer cells. Existing methods for detecting ALT in tumors require substantial amounts of tumor material and are labor intensive, making it difficult to study prevalence and prognostic significance of ALT in large tumor cohorts. Here, we present a novel strategy utilizing telomere quantitative PCR to diagnose ALT. The protocol is more rapid than conventional methods and scrutinizes two distinct characteristics of ALT cells concurrently: long telomeres and the presence of C-circles (partially double-stranded circles of telomeric C-strand DNA). Requiring only 30 ng of genomic DNA, this protocol will facilitate large-scale studies of ALT in tumors and can be readily adopted by clinical laboratories.
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Neoplasias/genética , Reação em Cadeia da Polimerase/métodos , Homeostase do Telômero , Linhagem Celular Tumoral , DNA de Neoplasias/análise , Humanos , Sondas de Oligonucleotídeos , Telômero/químicaRESUMO
Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere length maintenance mechanism that enables the unlimited proliferation of a subset of cancer cells. Some neuroblastoma (NB) tumors appear to maintain telomere length by activating ALT. Of 40 NB cell lines, we identified four potential ALT cell lines (CHLA-90, SK-N-FI, LA-N-6, and COG-N-291) that were telomerase-negative and had long telomeres (a feature of ALT cells). All four cell lines lacked MYCN amplification and were p53 non-functional upon irradiation. Two of these cell lines (CHLA-90 and SK-N-FI) were positive for C-circles (telomeric DNA circles) and ALT-associated promyelocytic leukemia nuclear bodies, both of which are phenotypic characteristics of ALT. Mutation of ATRX (associated with ALT in tumors) was only found in CHLA-90. Thus, the ALT phenotype in NB may not be limited to tumors with ATRX mutations but is associated with a lack of MYCN amplification and alterations in the p53 pathway.
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Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Transdução de Sinais/genética , Homeostase do Telômero , Telômero/genética , Proteína Supressora de Tumor p53/genética , Linhagem Celular Tumoral , Amplificação de Genes , Humanos , Proteína Proto-Oncogênica N-Myc , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/metabolismo , Telômero/metabolismo , Proteína Supressora de Tumor p53/metabolismoRESUMO
Background: FUS-TFCP2 gene fusion is a recently identified and highly distinct molecular subtype of spindle cell/sclerosing rhabdomyosarcoma (RMS), with fewer than 40 cases being reported to date. Due to its low incidence, clinical studies on this subtype are limited. Here, we report a new case of this rare entity to describe and summarize its unique clinical characteristics and treatment process, aiming to emphasize the importance of molecular testing for spindle cell/sclerosing RMS and increase the understanding of this subtype. By summarizing and comparing with previous reports on RMS with the EWSR1/FUS-TFCP2 fusion mutation, we hope to make some new hints for its management. Case Description: In this report, we describe a rare case of spindle cell/sclerosing RMS in a 13-year-old boy, who had a massive destructive lesion involving the mandible. Next-generation sequencing of tumor tissue revealing a FUS-TFCP2 fusion. The tumor was extremely aggressive and showed resistance to polychemotherapy, after 4 cycles of multi drug combined chemotherapy, the primary tumor still continued to grow, and suspicious chest metastasis occurred. Even after aggressive total resection of the primary tumor and postoperative chemotherapy, systemic metastasis to the vertebra and chest could not be prevented yet, ultimately with a fatal outcome within 6 months. We additionally summarize 37 cases of RMS with the EWSR1/FUS-TFCP2 fusion mutation reported in the literature. This subtype was found to be almost exclusively primary in bone and histologically showed a common origin of epithelium and muscle. The high aggressiveness made the conventional standard chemoradiotherapy ineffective. Because most tumors of this subtype express ALK protein, ALK inhibitors seem to be a new target for its therapy. Conclusions: Spindle cell/sclerosing RMS with FUS-TFCP2 fusion has its unique clinical characteristics and progression. It shows a marked skeletal predilection and an aggressive clinical course, typically resistant to traditional standard treatments for RMS. Therefore, molecular detection is crucial in managing this subtype. Once the diagnosis is clear, a more aggressive treatment plan is needed. In addition, almost all cases were found to have a positive expression of ALK. So ALK inhibitors can be a choice of targeted therapy.
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HMGA2::NCOR2 keratin-positive giant cell tumors in children with response to imatinib in an infant.
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Proteína HMGA2 , Mesilato de Imatinib , Neoplasias de Tecidos Moles , Feminino , Humanos , Lactente , Masculino , Antineoplásicos/uso terapêutico , Neoplasias Ósseas/tratamento farmacológico , Tumor de Células Gigantes do Osso/tratamento farmacológico , Tumor de Células Gigantes do Osso/genética , Proteína HMGA2/genética , Mesilato de Imatinib/uso terapêutico , Queratinas , Neoplasias de Tecidos Moles/tratamento farmacológico , Neoplasias de Tecidos Moles/patologia , Neoplasias de Tecidos Moles/genéticaRESUMO
Recent research showed that precision medicine can identify new treatment strategies for patients with childhood cancers. However, it is unclear which patients will benefit most from precision-guided treatment (PGT). Here we report consecutive data from 384 patients with high-risk pediatric cancer (with an expected cure rate of less than 30%) who had at least 18 months of follow-up on the ZERO Childhood Cancer Precision Medicine Program PRecISion Medicine for Children with Cancer (PRISM) trial. A total of 256 (67%) patients received PGT recommendations and 110 (29%) received a recommended treatment. PGT resulted in a 36% objective response rate and improved 2-year progression-free survival compared with standard of care (26% versus 12%; P = 0.049) or targeted agents not guided by molecular findings (26% versus 5.2%; P = 0.003). PGT based on tier 1 evidence, PGT targeting fusions or commenced before disease progression had the greatest clinical benefit. Our data show that PGT informed by comprehensive molecular profiling significantly improves outcomes for children with high-risk cancers. ClinicalTrials.gov registration: NCT03336931.
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Neoplasias , Medicina de Precisão , Humanos , Medicina de Precisão/métodos , Criança , Neoplasias/genética , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Feminino , Masculino , Adolescente , Pré-Escolar , Lactente , Intervalo Livre de Progressão , Resultado do TratamentoRESUMO
Diffuse midline gliomas (DMG) harbouring H3K27M mutation are paediatric tumours with a dismal outcome. Recently, a new subtype of midline gliomas has been described with similar features to DMG, including loss of H3K27 trimethylation, but lacking the canonical H3K27M mutation (H3-WT). Here, we report a cohort of five H3-WT tumours profiled by whole-genome sequencing, RNA sequencing and DNA methylation profiling and combine their analysis with previously published cases. We show that these tumours have recurrent and mutually exclusive mutations in either ACVR1 or EGFR and are characterised by high expression of EZHIP associated to its promoter hypomethylation. Affected patients share a similar poor prognosis as patients with H3K27M DMG. Global molecular analysis of H3-WT and H3K27M DMG reveal distinct transcriptome and methylome profiles including differential methylation of homeobox genes involved in development and cellular differentiation. Patients have distinct clinical features, with a trend demonstrating ACVR1 mutations occurring in H3-WT tumours at an older age. This in-depth exploration of H3-WT tumours further characterises this novel DMG, H3K27-altered sub-group, characterised by a specific immunohistochemistry profile with H3K27me3 loss, wild-type H3K27M and positive EZHIP. It also gives new insights into the possible mechanism and pathway regulation in these tumours, potentially opening new therapeutic avenues for these tumours which have no known effective treatment. This study has been retrospectively registered on clinicaltrial.gov on 8 November 2017 under the registration number NCT03336931 ( https://clinicaltrials.gov/ct2/show/NCT03336931 ).
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Genes Homeobox , Glioma , Criança , Humanos , Histonas/genética , Metilação , Glioma/genética , Mutação , Receptores ErbB/genética , Receptores de Ativinas Tipo IRESUMO
Precision medicine programs aim to utilize novel technologies to identify personalized treatments for children with cancer. Delivering these programs requires interdisciplinary efforts, yet the many groups involved are understudied. This study explored the experiences of a broad range of professionals delivering Australia's first precision medicine trial for children with poor-prognosis cancer: the PRecISion Medicine for Children with Cancer (PRISM) national clinical trial of the Zero Childhood Cancer Program. We conducted semi-structured interviews with 85 PRISM professionals from eight professional groups, including oncologists, surgeons, clinical research associates, scientists, genetic professionals, pathologists, animal care technicians, and nurses. We analyzed interviews thematically. Professionals shared that precision medicine can add complexity to their role and result in less certain outcomes for families. Although many participants described experiencing a greater emotional impact from their work, most expressed very positive views about the impact of precision medicine on their profession and its future potential. Most reported navigating precision medicine without formal training. Each group described unique challenges involved in adapting to precision medicine in their profession. Addressing training gaps and meeting the specific needs of many professional groups involved in precision medicine will be essential to ensure the successful implementation of standard care.
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INTRODUCTION: Identifying an underlying germline cancer predisposition (CP) in a child with cancer has potentially significant implications for both the child and biological relatives. Cohort studies indicate that 10%-15% of paediatric cancer patients carry germline pathogenic or likely pathogenic variants in cancer predisposition genes, but many of these patients do not meet current clinical criteria for genetic testing. This suggests broad tumour agnostic germline testing may benefit paediatric cancer patients. However, the utility and psychosocial impact of this approach remain unknown. We hypothesise that an approach involving trio whole-genome germline sequencing (trio WGS) will identify children and families with an underlying CP in a timely fashion, that the trio design will streamline cancer risk counselling to at-risk relatives if CP was inherited, and that trio testing will not have a negative psychosocial impact on families. METHOD AND ANALYSIS: To test this, we present the Cancer PREDisposition In Childhood by Trio sequencing study (PREDICT). This study will assess the clinical utility of trio WGS to identify CP in unselected patients with cancer 21 years or younger in New South Wales, Australia. PREDICT will perform analysis of biological parents to determine heritability and will examine the psychosocial impact of this trio sequencing approach. PREDICT also includes a broad genomics research programme to identify new candidate genes associated with childhood cancer risk. ETHICS AND DISSEMINATION: By evaluating the feasibility, utility and psychosocial impact of trio WGS to identify CP in paediatric cancer, PREDICT will inform how such comprehensive testing can be incorporated into a standard of care at diagnosis for all childhood cancer patients. TRIAL REGISTRATION NUMBER: NCT04903782.
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Neoplasias , Adolescente , Criança , Humanos , Estudos de Coortes , Suscetibilidade a Doenças , Predisposição Genética para Doença , Neoplasias/diagnóstico , Neoplasias/genética , Estudos Prospectivos , Sequenciamento Completo do Genoma/métodosRESUMO
For one-third of patients with pediatric cancer enrolled in precision medicine programs, molecular profiling does not result in a therapeutic recommendation. To identify potential strategies for treating these high-risk pediatric patients, we performed in vitro screening of 125 patient-derived samples against a library of 126 anticancer drugs. Tumor cell expansion did not influence drug responses, and 82% of the screens on expanded tumor cells were completed while the patients were still under clinical care. High-throughput drug screening (HTS) confirmed known associations between activating genomic alterations in NTRK, BRAF, and ALK and responses to matching targeted drugs. The in vitro results were further validated in patient-derived xenograft models in vivo and were consistent with clinical responses in treated patients. In addition, effective combinations could be predicted by correlating sensitivity profiles between drugs. Furthermore, molecular integration with HTS identified biomarkers of sensitivity to WEE1 and MEK inhibition. Incorporating HTS into precision medicine programs is a powerful tool to accelerate the improved identification of effective biomarker-driven therapeutic strategies for treating high-risk pediatric cancers. SIGNIFICANCE: Integrating HTS with molecular profiling is a powerful tool for expanding precision medicine to support drug treatment recommendations and broaden the therapeutic options available to high-risk pediatric cancers.
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Antineoplásicos , Neoplasias , Humanos , Criança , Avaliação Pré-Clínica de Medicamentos , Detecção Precoce de Câncer , Neoplasias/tratamento farmacológico , Neoplasias/genética , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Ensaios de Triagem em Larga Escala/métodosRESUMO
BACKGROUND: Molecular profiling of the tumour immune microenvironment (TIME) has enabled the rational choice of immunotherapies in some adult cancers. In contrast, the TIME of paediatric cancers is relatively unexplored. We speculated that a more refined appreciation of the TIME in childhood cancers, rather than a reliance on commonly used biomarkers such as tumour mutation burden (TMB), neoantigen load and PD-L1 expression, is an essential prerequisite for improved immunotherapies in childhood solid cancers. METHODS: We combined immunohistochemistry (IHC) with RNA sequencing and whole-genome sequencing across a diverse spectrum of high-risk paediatric cancers to develop an alternative, expression-based signature associated with CD8+ T-cell infiltration of the TIME. Furthermore, we explored transcriptional features of immune archetypes and T-cell receptor sequencing diversity, assessed the relationship between CD8+ and CD4+ abundance by IHC and deconvolution predictions and assessed the common adult biomarkers such as neoantigen load and TMB. RESULTS: A novel 15-gene immune signature, Immune Paediatric Signature Score (IPASS), was identified. Using this signature, we estimate up to 31% of high-risk cancers harbour infiltrating T-cells. In addition, we showed that PD-L1 protein expression is poorly correlated with PD-L1 RNA expression and TMB and neoantigen load are not predictive of T-cell infiltration in paediatrics. Furthermore, deconvolution algorithms are only weakly correlated with IHC measurements of T-cells. CONCLUSIONS: Our data provides new insights into the variable immune-suppressive mechanisms dampening responses in paediatric solid cancers. Effective immune-based interventions in high-risk paediatric cancer will require individualised analysis of the TIME.
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Antígeno B7-H1 , Neoplasias , Adulto , Humanos , Criança , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Neoplasias/genética , Linfócitos T CD8-Positivos/metabolismo , Biomarcadores Tumorais/genética , Microambiente Tumoral/genética , MutaçãoRESUMO
Motivation: Changes in telomere length have been observed in cancer and can be indicative of mechanisms involved in carcinogenesis. Most methods used to estimate telomere length require laboratory analysis of DNA samples. Here, we present qmotif, a fast and easy tool that determines telomeric repeat sequences content as an estimate of telomere length directly from whole-genome sequencing. Results: qmotif shows similar results to quantitative PCR, the standard method for high-throughput clinical telomere length quantification. qmotif output correlates strongly with the output of other tools for determining telomere sequence content, TelSeq and TelomereHunter, but can run in a fraction of the time-usually under a minute. Availability and implementation: qmotif is implemented in Java and source code is available at https://github.com/AdamaJava/adamajava, with instructions on how to build and use the application available from https://adamajava.readthedocs.io/en/latest/. Supplementary information: Supplementary data are available at Bioinformatics Advances online.
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Biomarkers which better match anticancer drugs with cancer driver genes hold the promise of improved clinical responses and cure rates. We developed a precision medicine platform of rapid high-throughput drug screening (HTS) and patient-derived xenografting (PDX) of primary tumor tissue, and evaluated its potential for treatment identification among 56 consecutively enrolled high-risk pediatric cancer patients, compared with conventional molecular genomics and transcriptomics. Drug hits were seen in the majority of HTS and PDX screens, which identified therapeutic options for 10 patients for whom no targetable molecular lesions could be found. Screens also provided orthogonal proof of drug efficacy suggested by molecular analyses and negative results for some molecular findings. We identified treatment options across the whole testing platform for 70% of patients. Only molecular therapeutic recommendations were provided to treating oncologists and led to a change in therapy in 53% of patients, of whom 29% had clinical benefit. These data indicate that in vitro and in vivo drug screening of tumor cells could increase therapeutic options and improve clinical outcomes for high-risk pediatric cancer patients.
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Antineoplásicos , Neoplasias , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Criança , Modelos Animais de Doenças , Genômica/métodos , Humanos , Neoplasias/patologia , Medicina de Precisão/métodos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Diffuse leptomeningeal glioneuronal tumours (DLGNT) represent rare enigmatic CNS tumours of childhood. Most patients with this disease share common radiological and histopathological features but the clinical course of this disease is variable. A radiological hallmark of this disease is widespread leptomeningeal enhancement that may involve the entire neuroaxis with predilection for the posterior fossa and spine. The classic pathologic features include low- to moderate-density cellular lesions with OLIG2 expression and evidence of 'oligodendroglioma-like' appearance. The MAPK/ERK signaling pathway has recently been reported as a potential driver of tumourigenesis in up to 80% of DLGNT with KIAA1549:BRAF fusions being the most common event seen. Until now, limited analysis of the biological drivers of tumourigenesis has been undertaken via targeted profiling, chromosomal analysis and immunohistochemistry. Our study represents the first examples of comprehensive genomic sequencing in DLGNT and shows that it is not only feasible but crucial to our understanding of this rare disease. Moreover, we demonstrate that DLGNT may be more genomically complex than single-event MAPK/ERK signaling pathway tumours.
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Neoplasias Encefálicas/genética , Genômica/métodos , Neoplasias Meníngeas/genética , Meningioma/genética , Neoplasias da Medula Espinal/genética , Adolescente , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/tratamento farmacológico , Criança , Feminino , Humanos , Masculino , Neoplasias Meníngeas/diagnóstico , Neoplasias Meníngeas/tratamento farmacológico , Meningioma/diagnóstico , Meningioma/tratamento farmacológico , Neoplasias da Medula Espinal/diagnóstico , Neoplasias da Medula Espinal/tratamento farmacológicoRESUMO
C-Circles, self-primed telomeric C-strand templates for rolling circle amplification, are the only known alternative-lengthening-of-telomeres (ALT)-specific molecule. However, little is known about the biology of C-Circles and if they may be clinically useful. Here we show that C-Circles are secreted by ALT+ cancer cells inside exosomes, and that a blood-based C-Circle Assay (CCA) can provide an accurate diagnostic for ALT activity. Extracellular vesicles were isolated by differential centrifugation from the growth media of lung adenocarcinoma, glioblastoma, neuroblastoma, osteosarcoma, and soft tissue sarcoma cell lines, and C-Circles were detected in the exosome fraction from all eleven ALT+ cancer cell lines and not in any extracellular fraction from the eight matching telomerase positive cancer cell lines or the normal fibroblast strain. The existence of C-Circles in ALT+ exosomes was confirmed with exosomes isolated by iodixanol gradient separation and CD81-immunoprecipitation, and C-Circles in the exosomes were protected from nucleases. On average, 0.4% of the total ALT+ intracellular C-Circles were secreted in the exosomes every 24 h. Comparing the serum-based and tumor-based CCAs in 35 high risk neuroblastoma patients divided randomly into ALT+ threshold derivation and validation groups, we found the serum-based CCA to have 100% sensitivity (6/6), 70% specificity (7/10), and 81% concordance (13/16). We conclude that the secretion of C-Circles by ALT+ cancer cells in the exosomes provides a stable blood-based biomarker and a potential clinical diagnostic for ALT activity.
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The prognosis of recurrent malignant peripheral nerve sheath tumors (MPNST) is dismal, with surgical resection being the only definitive salvage therapy. Treatment with chemoradiation approaches has not significantly improved patient outcomes. Similarly, trials of therapies targeting MPNST genomic drivers have thus far been unsuccessful. Improved understanding of the molecular pathogenesis of MPNST indicates frequent activation of the mitogen-activated protein kinase (MAPK) cell signaling pathway. MEK inhibitors have shown activity in preclinical studies; however, their clinical efficacy has not been reported to date. We describe here a case of sustained complete response to MEK inhibition in an adolescent patient with a recurrent metastatic MPNST with multiple alterations in the MAPK pathway, guided by a precision oncology approach.