Segmental Chromosomal Alterations Research Articles

Chromosome instability in neuroblastoma: A pathway to aggressive disease.

For over 100-years, genomic instability has been investigated as a central player in the pathogenesis of human cancer. Conceptually, genomic instability includes an array of alterations from small deletions/insertions to whole chromosome alterations, referred to as chromosome instability. Chromosome instability has a paradoxical impact in cancer. In most instances, the introduction of chromosome instability has a negative impact on cellular fitness whereas in cancer it is usually associated with a worse prognosis. One exception is the case of neuroblastoma, the most common solid tumor outside of the brain in children. Neuroblastoma tumors have two distinct patterns of genome instability: whole-chromosome aneuploidy, which is associated with a better prognosis, or segmental chromosomal alterations, which is a potent negative prognostic factor. Through a computational screen, we found that low levels of the de- ubiquitinating enzyme USP24 have a highly significant negative impact on survival in neuroblastoma. At the molecular level, USP24 loss leads to destabilization of the microtubule assembly factor CRMP2 - producing mitotic errors and leading to chromosome missegregation and whole-chromosome aneuploidy. This apparent paradox may be reconciled through a model in which whole chromosome aneuploidy leads to the subsequent development of segmental chromosome alterations. Here we review the mechanisms behind chromosome instability and the evidence for the progressive development of segmental alterations from existing numerical aneuploidy in support of a multi-step model of neuroblastoma progression.

P-532 Embryo aneuploidy risk is increased in couples with unexplained infertility

Abstract Study question Are chromosomal abnormalities (aneuploidy and mosaicism) increased in couples with unexplained infertility? Summary answer Couples with unexplained infertility show higher rates of embryo aneuploidy compared to IVF with donor sperm cycles. What is known already Aneuploidy is the most common genetic abnormality found in early embryos. Although there is strong evidence about the correlation between oocyte age and aneuploidy rates, the potential contribution of additional female and male factor warrants further elucidation. Unexplained infertility is a diagnosed of exclusion affecting ∼30% of couples seeking infertility care. Recent medical evidence suggests that these couples have lower odds of having a live birth compared to their counterparts using donor sperm. Therefore, the aim of this study was to elucidate whether chromosomal abnormalities (aneuploidy and mosaicism) were increased in couples with unexplained infertility. Study design, size, duration Retrospective analysis of the chromosomic evaluation of 700 embryos coming from 220 IVF/PGT-A cycles (March 2017 - September 2021) performed in a private fertility center. The comprehensive chromosome screening included testing for aneuploidy and mosaicism. In addition, whole and segmental chromosomal alterations were also identified and reported. Participants/materials, setting, methods Participants were divided into two groups: couples with unexplained infertility (study group) and women undergoing IVF using donated sperm (control group). Only normospermic and normal sperm FISH samples were included. The Veriseq NGS (Illumina) platform was employed for PGT-A testing. An SPSSv20.0 logistic regression analysis was performed for aneuploidy and mosaicism rate. The resulted odds ratio was then adjusted to account for: female/male age, previous implantation failure, recurrent pregnancy loss, previous chromosomopathies and embryo quality. Main results and the role of chance A total of 220 PGT-A cycles were included in the analysis (study group n = 94 vs control group n = 126) comprising 700 embryos (study group n = 313 vs control group n = 387). The female age was 38.17 ± 3.6 vs 40.08 ± 2.4 and the male age was 40.57 ± 5.0 and 25.37 ± 3.8, in the study vs control groups, respectively. Unexplained infertility couples showed a higher risk for generating aneuploid embryos compared to IVF with donor sperm cycles [OR = 2.33 IC 95% (1.11-5.00)]. In addition, whole chromosomal alterations [OR = 2.11 IC 95% (1.00-4.44)] as well as segmental chromosomal alterations rate [OR = 1.38 IC 95% (0.49-3.86)], were higher in unexplained infertility couples, but without reaching statistical significance. Regarding to mosaicism rate, no significant differences were found between groups: overall [OR = 0.74 IC 95% (0.30-1.83)], whole chromosome [OR = 0.92 IC 95% (0.35-2.46)] and segmental chromosomal [OR = 0.36 IC95% (0.10-1.34)] mosaicism. Limitations, reasons for caution The inherent limitations of a retrospective analysis. Additional studies are warranted to clarify the potential factors explaining the higher embryo aneuploidy risk in this sub-set of patients. Wider implications of the findings Our data suggest an increased risk for embryo aneuploidy in unexplained infertility couples undergoing ART. Since the treatment for these couples is largely empirical, our results emphasize the importance of PGT-A analysis as a potential strategy for unexplained infertility patients. Trial registration number Not applicable

RARE-08. Profiling of recurrent adamantinomatous cranionpharyngioma confirms the activation of the MAPK pathway and identifies copy number aberrations in relapsed tumours

Craniopharyngiomas are rare challenging tumours, with around 25% of cases recurring despite surgery and/or radiotherapy. Whilst transcriptomic and proteomic profiling of adamantinomatous craniopharyngioma (ACP) have revealed activation of the MAPK pathway and IL-6 mediated inflammation, relatively little is known about the biological processes involved in tumour recurrence. To address this, we have analysed a cohort of primary and relapsed ACP tumour accessed from tissue banks, local pathology departments and international collaborators. Serial samples of recurrent ACP (n=11), recurrent papillary craniopharyngioma (PCP) (n=4) and 3 non-recurrent ACP were analysed using β-catenin, pERK1/2 immunostaining, DNA methylation array and RNA sequencing. Differential expression and methylation analyses confirmed differences between ACP and PCP, with over representation of WNT pathway genes in ACP and the MAPK pathway genes in PCP. All of the primary and all except for one of the relapsed ACP tumours showed a pERK1/2 expression. Differences in the immune environment were also identified between ACP and PCP, with higher levels of some inflammatory mediators and CD14+ cell signatures in PCP compared with ACP. Whilst differential methylation and expression analysis revealed relatively stable methylomes and transcriptomes between serial samples of cases, segmental chromosomal alterations were identified in recurrence samples from five ACP cases (5/11,45%). One relapsed case showed histological and molecular signs of malignant transformation, including high ki67 and deletion of TP53. Surprisingly, this malignant tumour showed nuclear beta-catenin in all neoplastic epithelial cells and absence of pERK1/2 staining, despite the primary tumour showing the typical beta-catenin and pERK1/2 expression patterns. These results suggest that the molecular landscape of craniopharyngioma remains stable between recurrences in most cases, but, there is evidence of molecular evolution in a subset of cases. Activation of the MAPK pathway in the vast majority of ACP tumours supports the clinical evaluation of MAPK pathway inhibitors in ACP patients.

Long-Term Outcome and Role of Biology within Risk-Adapted Treatment Strategies: The Austrian Neuroblastoma Trial A-NB94.

Simple SummaryNeuroblastoma, the most common extracranial malignancy of childhood, shows a highly variable course of disease ranging from spontaneous regression or maturation into a benign tumor to an aggressive and intractable cancer in up to 60% of patients. To adapt treatment intensity, risk staging at diagnosis is of utmost importance. The A-NB94 trial was the first in Austria to stratify therapy intensity according to tumor staging, patient’s age, and MYCN amplification status, the latter being a biologic marker turning otherwise low-risk tumors into high-risk disease. Recent publications showed a prognostic impact of various genomic features including segmental chromosomal aberrations (SCAs). We retrospectively investigated the relevance of SCAs within this risk-adapted treatment strategy. The A-NB94 approach resulted in an excellent long-term survival for the majority of patients with acceptable long-term morbidity. An age- and stage-dependent frequency of SCAs was confirmed and SCAs should always be considered in future treatment decision making processes.We evaluated long-term outcome and genomic profiles in the Austrian Neuroblastoma Trial A-NB94 which applied a risk-adapted strategy of treatment (RAST) using stage, age and MYCN amplification (MNA) status for stratification. RAST ranged from surgery only to intensity-adjusted chemotherapy, single or multiple courses of high-dose chemotherapy (HDT) followed by autologous stem cell rescue depending on response to induction chemotherapy, and irradiation to the primary tumor site. Segmental chromosomal alterations (SCAs) were investigated retrospectively using multi- and pan-genomic techniques. The A-NB94 trial enrolled 163 patients. Patients with localized disease had an excellent ten-year (10y) event free survival (EFS) and overall survival (OS) of 99 ± 1% and 93 ± 2% whilst it was 80 ± 13% and 90 ± 9% for infants with stage 4S and for infants with stage 4 non-MNA disease both 83 ± 15%. Stage 4 patients either >12 months or ≤12 months but with MNA had a 10y-EFS and OS of 45 ± 8% and 47 ± 8%, respectively. SCAs were present in increasing frequencies according to stage and age: in 29% of localized tumors but in 92% of stage 4 tumors (p < 0.001), and in 39% of patients ≤ 12 months but in 63% of patients > 12 months (p < 0.001). RAST successfully reduced chemotherapy exposure in low- and intermediate-risk patients with excellent long-term results while the outcome of high-risk disease met contemporary trials.

Neuroblastoma: the association of anatomical tumour site, molecular biology and patient outcomes.

Numerous factors have been identified as carrying prognostic value in neuroblastoma (NB) and therefore incorporated in risk stratification of disease. Here, we investigate the association of anatomical site of NB with molecular biology and clinical outcomes. A total of 117 patients with NB were studied over a 30-year period. Tumour location was confirmed with computed tomography/magnetic resonance imaging. Data on molecular biology were obtained as testing became available. Chi-squared, Fisher's exact test and Kaplan-Meier log-rank tests were used for statistical analysis. Tumour originated in the thoracic region (thoracic NB, TNB) in 15 patients (13%), adrenal gland (adrenal NB, ANB) in 88 patients (75%) and abdominal/paravertebral chain (paravertebral NB, PVNB) in 14 patients (12%). Overall survival (OS) for ANB was significantly lower (38%; P= 0.015). ANB cases were more frequently diagnosed at stage IV (69%; P= 0.001). MYCN amplification was noted in 33% of ANB cases and associated with lower OS (17% versus 62% MYCN non-amplified ANB; P= 0.01). The vast majority of TNB and PVNB were non-MYCN amplified (100% and 86%, respectively) and carried better prognosis (OS 86% and 83%, respectively). Forty-two percent of ANB cases were diploid and had lower OS (20% versus 71% hyperdiploid ANB; P= 0.079). TNB and PVNB were found to be mostly hyperdiploid (86% and 100%, respectively) with better OS (83% and 33%, respectively). Segmental chromosomal alterations had prognostic significance in those with PVNB (P= 0.03). TNB tumours have better outcomes than adrenal tumours. This may be due to varied factors reported here including non-metastatic disease at presentation, non-amplification of the MYCN oncogene and overall favourable molecular biology characteristics.

Distribution of segmental chromosomal alterations in neuroblastoma.

Neuroblastoma (NB) is a heterogeneous tumor with extremely diverse prognosis according to clinical and genetic factors such as specific combinations of chromosomal imbalances. Molecular karyotyping data from a national neuroblastic tumor database of 155 NB samples were analyzed and related to clinical data. Segmental chromosomal alterations (SCA) were detected in 102 NB, whereas 45 only displayed numerical alterations. Incidence of SCA was higher in stage M (92%) and MYCN amplified (MNA) NB (96%). Presence of SCA was associated with older age, especially 1q gain and 3p deletion. 96% of the deaths were observed in the SCA group and 85% of the relapsed NB contained SCA. The alteration most commonly associated with a higher number of other segmental rearrangements was 11q deletion, followed by 4p deletion. Whole-chromosome 19 gain was associated with lower stages, absence of SCA and better outcome. SCA are not randomly distributed and are concentrated on recurrent chromosomes. The most frequently affected chromosomes identify prognostic factors in specific risk groups. SCA are associated with older age and MNA. We have identified a small subset of patients with better outcome that share whole-chromosome 19 numeric gain, suggesting its use as a prognostic biomarker in NB.

Abstract B30: ARID1A is a haploinsufficient tumor suppressor for N-Myc transformation of neural crest cells

Abstract Large segmental chromosomal alterations are common to cancer and a feature of high-risk neuroblastoma (NBL). Though they are early or initiating events in cancer, including often being found in precancerous lesions, their contribution to tumorigenesis is poorly understood. An unproven model is that these changes promote cancer through the cumulative effect of multiple dosage-sensitive genes. Loss of heterozygosity (LOH) at 1p36 is a frequent structural rearrangement in a broad range of human cancers including NBL. Approximately 70% of MYCN amplified NBL have 1p36 LOH with both mutations independently contributing to tumor aggressiveness in NBL. Two tumor suppressor regions have been proposed to exist in 1p36, a distal and proximal region, which have MYCN-independent and dependent roles. Through CRISPR/Cas9 genome editing of primary mouse neural crest cells (NCCs), a source for NBL, we found that loss of the chromatin remodeling factor Chd5 conferred most of the tumor-suppressor effects of 1p36 LOH in in vitro cell transformation assays in cells with endogenous levels of N-Myc. In contrast, when N-Myc was overexpressed, tumor evolution of NCCs genome edited to have randomly sized 1p36 deletions showed a reduction in tumor latency that significantly correlated with deletion of Arid1a. The Arid1a deletions that were selected for ranged from small indels up to large 1p36 deletions, indicating that large deletions are tolerated to achieve loss of a single critical tumor suppressor. Further, using lentiviral Cre-induced deletion of floxed Arid1a in isolated NCCs, we found that Arid1a is a haploinsufficient tumor suppressor in MYCN-driven transformation of NCCs. As Arid1a is a subunit of the chromatin remodeling complex SWI/SNF, which is mutated in 20% of cancers, Arid1a synthetic lethal therapies are being developed for adult malignancies. We are currently verifying those proposed therapies in NBL and are using small-molecule screening of cells lines derived from Arid1a wild-type, het, or null tumors to identify additional synthetic lethalities. Our findings indicate that context, such as the status of MYCN as an oncogene, dictates which 1p36 gene is the critical tumor suppressor, establishing 1p36 LOH as multifaceted not cumulative, as was previously believed. Citation Format: Kirby Wallace, Jesus Garcia-Lopez, Joel Otero, Rachelle Olsen, Chelsea DeVaux, Ashton King, Andrew Davidoff, Kevin Freeman. ARID1A is a haploinsufficient tumor suppressor for N-Myc transformation of neural crest cells [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B30.

Identification Of Actionable Genetic Targets In Primary Cardiac Sarcomas.

BackgroundPrimary cardiac tumors are extremely rare; most are myxomas with a benign prognosis. However, primary sarcomas are highly aggressive and treatment options are limited. Radical surgery is often not feasible and conventional therapies provide only modest results. Due to the rare nature of primary cardiac tumors, there are no proper randomized studies to guide treatment. Their complexity requires alternative approaches in order to improve treatment efficacy.MethodsWe isolated DNA from 5 primary cardiac sarcomas; the quality of DNA from 3 of them was sufficient to perform high-resolution single nucleotide polymorphism (SNP) array analysis.ResultsIn the present study, molecular karyotyping revealed numerous segmental chromosomal alterations and amplifications affecting actionable genes that may be involved in disease initiation and/or progression. These include chromosomal break flanking AKT2 in undifferentiated pleomorphic rhabdomyosarcoma, chromosomal break in promoter of TERT, and gain of CDK4 and amplification of MDM2 in inflammatory myofibroblastic tumor. We detected segmental break flanking MOS in high-grade myxofibrosarcoma. In addition, the high number of chromosomal aberrations in high-grade myxofibrosarcoma may cause multiple tumor-specific epitopes, supporting the study of immunotherapy treatment in this type of aggressive tumor.ConclusionOur results provide a genetic rationale that supports an alternative, personalized therapeutic management of primary cardiac sarcomas.

Genomic Profiles of Neuroblastoma Associated With Opsoclonus Myoclonus Syndrome.

Opsoclonus myoclonus syndrome (OMS), often called "dancing eyed syndrome," is a rare neurological condition associated with neuroblastoma in the majority of all childhood cases. Genomic copy number profiles have shown to be of prognostic significance for neuroblastoma patients. The aim of this retrospective multicenter study was to analyze the genomic copy number profiles of tumors from children with neuroblastoma presenting with OMS at diagnosis. In 44 cases of neuroblastoma associated with OMS, overall genomic profiling by either array-comparative genomic hybridization or single nucleotide polymorphism array proved successful in 91% of the cases, distinguishing tumors harboring segmental chromosome alterations from those with numerical chromosome alterations only. A total of 23/44 (52%) tumors showed an segmental chromosome alterations genomic profile, 16/44 (36%) an numerical chromosome alterations genomic profile, and 1 case displayed an atypical profile (12q amplicon). No recurrently small interstitial copy number alterations were identified. With no tumor relapse nor disease-related deaths, the overall genomic profile was not of prognostic impact with regard to the oncological outcome in this series of patients. Thus, the observation of an excellent oncological outcome, even for those with an unfavorable genomic profile of neuroblastoma, supports the hypothesis that an immune response might be involved in tumor control in these patients with OMS.

Neuroblastoma.

Neuroblastoma is one of the most common solid tumors in children and has a diverse clinical behavior that largely depends on the tumor biology. Neuroblastoma exhibits unique features, such as early age of onset, high frequency of metastatic disease at diagnosis in patients over 1 year of age and the tendency for spontaneous regression of tumors in infants. The high-risk tumors frequently have amplification of the MYCN oncogene as well as segmental chromosome alterations with poor survival. Recent advanced genomic sequencing technology has revealed that mutation of ALK, which is present in ~10% of primary tumors, often causes familial neuroblastoma with germline mutation. However, the frequency of gene mutations is relatively small and other aberrations, such as epigenetic abnormalities, have also been proposed. The risk-stratified therapy was introduced by the Japan Neuroblastoma Study Group (JNBSG), which is now moving to the Neuroblastoma Committee of Japan Children's Cancer Group (JCCG). Several clinical studies have facilitated the reduction of therapy for children with low-risk neuroblastoma disease and the significant improvement of cure rates for patients with intermediate-risk as well as high-risk disease. Therapy for patients with high-risk disease includes intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy. The JCCG aims for better cures and long-term quality of life for children with cancer by facilitating new approaches targeting novel driver proteins, genetic pathways and the tumor microenvironment.

Triplications of human chromosome 21 orthologous regions in mice result in expansion of megakaryocyte-erythroid progenitors and reduction of granulocyte-macrophage progenitors.

Individuals with Down syndrome (DS) frequently have hematopoietic abnormalities, including transient myeloproliferative disorder and acute megakaryoblastic leukemia which are often accompanied by acquired GATA1 mutations that produce a truncated protein, GATA1s. The mouse has been used for modeling DS based on the syntenic conservation between human chromosome 21 (Hsa21) and three regions in the mouse genome located on mouse chromosome 10 (Mmu10), Mmu16 and Mmu17. To assess the impact of the dosage increase of Hsa21 gene orthologs on the hematopoietic system, we characterized the related phenotype in the Dp(10)1Yey/+;Dp(16)1Yey/+;Dp(17)1Yey/+ model which carries duplications spanning the entire Hsa21 orthologous regions on Mmu10, Mmu16 and Mmu17, and the Dp(10)1Yey/+;Dp(16)1Yey/+;Dp(17)1Yey/+;Gata1Yeym2 model which carries a Gata1s mutation we engineered. Both models exhibited anemia, macrocytosis, and myeloproliferative disorder. Similar to human DS, the megakaryocyte-erythrocyte progenitors (MEPs) and granulocyte-monocyte progenitors (GMPs) were significantly increased and reduced, respectively, in both models. The subsequent identification of all the aforementioned phenotypes in the Dp(16)1Yey/+ model suggests that the causative dosage sensitive gene(s) are in the Hsa21 orthologous region on Mmu16. Therefore, we reveal here for the first time that the human trisomy 21-associated major segmental chromosomal alterations in mice can lead to expanded MEP and reduced GMP populations, mimicking the dynamics of these myeloid progenitors in DS. These models will provide the critical systems for unraveling the molecular and cellular mechanism of DS-associated myeloproliferative disorder, and particularly for determining how human trisomy 21 leads to expansion of MEPs as well as how such an alteration leads to myeloproliferative disorder.

Radiogenomics of neuroblastomas: Relationships between imaging phenotypes, tumor genomic profile and survival.

PurposeThis study investigated relationships between neuroblastomas (NBs) imaging phenotypes, tumor genomic profile and patient outcome.Patients and methodsThis IRB-approved retrospective observational study included 133 NB patients (73 M, 60 F; median age 15 months, range 0–151) treated in a single institution between 1998 and 2012. A consensus review of imaging (CT-scan, MRI) categorized tumors according to both the primarily involved compartment (i.e., neck, chest, abdomen or pelvis) and the sympathetic anatomical structure the tumors rose from (i.e., cervical, paravertebral or periarterial chains, or adrenal gland). Tumor shape, volume and image-defined surgical risk factors (IDRFs) at diagnosis were recorded. Genomic profiles were assessed using array-based comparative genomic hybridization and divided into three groups: “numerical-only chromosome alterations” (NCA), “segmental chromosome alterations” (SCA) and “MYCN amplification” (MNA). Statistical analyses included Kruskal–Wallis, Chi2 and Fisher’s exact tests and the Kaplan-Meier method with log-rank tests and Cox model for univariate and multivariate survival analyses.ResultsA significant association between the sympathetic structure origin of tumors and genomic profiles was demonstrated. NBs arising from cervical sympathetic chains were all NCA. Paravertebral NBs were NCA or SCA in 75% and 25%, respectively and none were MNA. Periarterial NBs were NCA, SCA or MNA in 33%, 56% and 11%, respectively. Adrenal NBs were NCA, SCA or MNA in 16%, 36% and 48%, respectively. Among MNA NBs, 92% originated from the adrenal gland. The sympathetic anatomical classification was significantly better correlated to overall survival than the compartmental classification (P < .0003). The tumor volume of MNA NBs was significantly higher than NCA or SCA NBs (P < .0001). Patients with initial volume less than 160 mL had significantly better overall survival (P < .009). A “single mass” pattern was significantly more frequent in NCA NBs (P = .0003). The number of IDRFs was significantly higher in MNA NBs (P < .0001).ConclusionImaging phenotypes of neuroblastomas, including tumor origin along the sympathetic system, correlate with tumor genomic profile and patient outcome.

Characterization of Chromosomal Aberrations in Neuroblastoma Formalin-Fixed Paraffin- Embedded Specimens with Standard ArrayCGH Procedure - Preliminary Experience

Background: The broad spectrum of neuroblastoma (NB) clinical behavior depends on a genomic landscape of tumor cells. The amplification of MYCN oncogene is the most powerful negative prognostic marker in NB. Moreover, segmental chromosomal alterations are also associated with a poor outcome. Therefore, the comprehensive characterization of tumor genetic features is obligatory for NB patients. These features determine the risk stratification and therapeutic decisions in treatment. Purpose: Our report focuses on a possibility to use standard microarray procedure to demonstrate critical structural chromosomal alteration in archival samples of NB tumors. Methods and Findings: Formalin-fixed paraffin-embedded tissue samples from 8 NB primary tumors have been analyzed by cytogenetic microarrays. It achieved a very good quality of genomic DNA from fixed samples. Chromosomal abnormalities were detected in 7 out of 8 cases. It was not an incidence of MYCN amplification. Conclusion: The results demonstrate that it is possible to obtain reliable and highquality microarray data from archival samples.

Genomic Copy Number Profiling Using Circulating Free Tumor DNA Highlights Heterogeneity in Neuroblastoma

The tumor genomic copy number profile is of prognostic significance in neuroblastoma patients. We have studied the genomic copy number profile of cell-free DNA (cfDNA) and compared this with primary tumor arrayCGH (aCGH) at diagnosis. In 70 patients, cfDNA genomic copy number profiling was performed using the OncoScan platform. The profiles were classified according to the overall pattern, including numerical chromosome alterations (NCA), segmental chromosome alterations (SCA), and MYCN amplification (MNA). Interpretable and dynamic cfDNA profiles were obtained in 66 of 70 and 52 of 70 cases, respectively. An overall identical genomic profile between tumor aCGH and cfDNA was observed in 47 cases (3 NCAs, 22 SCAs, 22 MNAs). In one case, cfDNA showed an additional SCA not detected by tumor aCGH. In 4 of 8 cases with a silent tumor aCGH profile, cfDNA analysis revealed a dynamic profile (3 SCAs, 1 NCA). In 14 cases, cfDNA analysis did not reveal any copy number changes. A total of 378 breakpoints common to the primary tumor and cfDNA of any given patient were identified, 27 breakpoints were seen by tumor aCGH, and 54 breakpoints were seen in cfDNA only, including two cases with interstitial IGFR1 gains and two alterations targeting TERT CONCLUSIONS: These results demonstrate the feasibility of cfDNA copy number profiling in neuroblastoma patients, with a concordance of the overall genomic profile in aCGH and cfDNA dynamic cases of 97% and a sensitivity of 77%, respectively. Furthermore, neuroblastoma heterogeneity is highlighted, suggesting that cfDNA might reflect genetic alterations of more aggressive cell clones. Clin Cancer Res; 22(22); 5564-73. ©2016 AACRSee related commentary by Janku and Kurzrock, p. 5400.

Neuroblastoma.

Neuroblastoma is the most common extracranial solid tumour occurring in childhood and has a diverse clinical presentation and course depending on the tumour biology. Unique features of these neuroendocrine tumours are the early age of onset, the high frequency of metastatic disease at diagnosis and the tendency for spontaneous regression of tumours in infancy. The most malignant tumours have amplification of the MYCN oncogene (encoding a transcription factor), which is usually associated with poor survival, even in localized disease. Although transgenic mouse models have shown that MYCN overexpression can be a tumour-initiating factor, many other cooperating genes and tumour suppressor genes are still under investigation and might also have a role in tumour development. Segmental chromosome alterations are frequent in neuroblastoma and are associated with worse outcome. The rare familial neuroblastomas are usually associated with germline mutations in ALK, which is mutated in 10-15% of primary tumours, and provides a potential therapeutic target. Risk-stratified therapy has facilitated the reduction of therapy for children with low-risk and intermediate-risk disease. Advances in therapy for patients with high-risk disease include intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy; these have improved 5-year overall survival to 50%. Currently, new approaches targeting the noradrenaline transporter, genetic pathways and the tumour microenvironment hold promise for further improvements in survival and long-term quality of life.

Diagnostic FDG and FDOPA positron emission tomography scans distinguish the genomic type and treatment outcome of neuroblastoma.

Neuroblastoma (NB) is a heterogeneous childhood cancer that requires multiple imaging modalities for accurate staging and surveillances. This study aims to investigate the utility of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) and 18F-fluoro-dihydroxyphenylalanine (FDOPA) in determining the prognosis of NB. During 2007–2014, forty-two NB patients (male:female, 28:14; median age, 2.0 years) undergoing paired FDG and FDOPA PET scans at diagnosis were evaluated for the maximum standardized uptake value (SUVmax) of FDG or FDOPA by the primary tumor. Patients with older age, advanced stages, or MYCN amplification showed higher FDG and lower FDOPA SUVmax (all P < 0.02). Receiver operating characteristics analysis identified FDG SUVmax≥ 3.31 and FDOPA SUVmax < 4.12 as an ultra-high-risk feature (PET-UHR) that distinguished the most unfavorable genomic types, i.e. segmental chromosomal alterations and/or MYCN amplification, at a sensitivity of 81.3% (54.4%–96.0%) and a specificity of 93.3% (68.1%–99.8%). Considering with age, stage, MYCN status, and anatomical image-defined risk factor, PET-UHR was an independent predictor of inferior event-free survival (multivariate hazard ratio, 4.9 [1.9–30.1]; P = 0.012). Meanwhile, the ratio between FDG and FDOPA SUVmax (G:D) correlated positively with HK2 (Spearman's ρ = 0.86, P < 0.0001) and negatively with DDC (ρ = −0.58, P = 0.02) gene expression levels, which might suggest higher glycolytic activity and less catecholaminergic differentiation in NB tumors taking up higher FDG and lower FDOPA. In conclusion, the intensity of FDG and FDOPA uptake on diagnostic PET scans may predict the tumor behavior and complement the current risk stratification systems of NB.

Advances in the translational genomics of neuroblastoma: From improving risk stratification and revealing novel biology to identifying actionable genomic alterations.

Neuroblastoma is an embryonal malignancy that commonly affects young children and is remarkably heterogenous in its malignant potential. Recently, the genetic basis of neuroblastoma has come into focus and not only has catalyzed a more comprehensive understanding of neuroblastoma tumorigenesis but also has revealed novel oncogenic vulnerabilities that are being therapeutically leveraged. Neuroblastoma is a model pediatric solid tumor in its use of recurrent genomic alterations, such as high-level MYCN (v-myc avian myelocytomatosis viral oncogene neuroblastoma-derived homolog) amplification, for risk stratification. Given the relative paucity of recurrent, activating, somatic point mutations or gene fusions in primary neuroblastoma tumors studied at initial diagnosis, innovative treatment approaches beyond small molecules targeting mutated or dysregulated kinases will be required moving forward to achieve noticeable improvements in overall patient survival. However, the clonally acquired, oncogenic aberrations in relapsed neuroblastomas are currently being defined and may offer an opportunity to improve patient outcomes with molecularly targeted therapy directed toward aberrantly regulated pathways in relapsed disease. This review summarizes the current state of knowledge about neuroblastoma genetics and genomics, highlighting the improved prognostication and potential therapeutic opportunities that have arisen from recent advances in understanding germline predisposition, recurrent segmental chromosomal alterations, somatic point mutations and translocations, and clonal evolution in relapsed neuroblastoma.

Oncologic Phenotype of Peripheral Neuroblastic Tumors Associated With PHOX2B Non-Polyalanine Repeat Expansion Mutations.

Germline non-polyalanine repeat expansion mutations in PHOX2B (PHOX2B NPARM) predispose to peripheral neuroblastic tumors (PNT), frequently in association with other neurocristopathies: Hirschsprung disease (HSCR) or congenital central hypoventilation syndrome (CCHS). Although PHOX2B polyalanine repeat expansions predispose to a low incidence of benign PNTs, the oncologic phenotype associated with PHOX2B NPARM is still not known in detail. We analyzed prognostic factors, treatment toxicity, and outcome of patients with PNT and PHOX2B NPARM. Thirteen patients were identified, six of whom also had CCHS and/or HSCR, one also had late-onset hypoventilation with hypothalamic dysfunction (LO-CHS/HD), and six had no other neurocristopathy. Four tumours were "poorly differentiated," and nine were differentiated, including five ganglioneuromas, three ganglioneuroblastomas, and one differentiating neuroblastoma, hence illustrating that PHOX2B NPARM are predominantly associated with differentiating tumors. Nevertheless, three patients had stage 4 and one patient had stage 3 disease. Segmental chromosomal alterations, correlating with poor prognosis, were found in all the six tumors analyzed by array-comparative genomic hybridization. One patient died of tumor progression, one is on palliative care, one died of hypoventilation, and 10 patients are still alive, with median follow-up of 5 years. Based on histological phenotype, our series suggests that heterozygous PHOX2B NPARM do not fully preclude ganglion cell differentiation in tumors. However, this tumor predisposition syndrome may also be associated with poorly differentiated tumors with unfavorable genomic profiles and clinically aggressive behaviors. The intrafamilial variability and the unpredictable tumor prognosis should be considered in genetic counseling.

Alternative NHEJ Pathway Components Are Therapeutic Targets in High-Risk Neuroblastoma

In neuroblastoma, MYCN genomic amplification and segmental chromosomal alterations including 1p or 11q loss of heterozygocity and/or 17q gain are associated with progression and poor clinical outcome. Segmental alterations are the strongest predictor of relapse and result from unbalanced translocations attributable to erroneous repair of chromosomal breaks. Although sequence analysis of affected genomic regions suggests that these errors arise by nonhomologous end-joining (NHEJ) of DNA double-strand breaks (DSB), abnormalities in NHEJ have not been implicated in neuroblastoma pathogenesis. On this basis, the hypothesis that an error-prone mechanism of NHEJ is critical for neuroblastoma cell survival was tested. Plasmid-based DSB repair assays demonstrated efficient NHEJ activity in human neuroblastoma cells with repair products that were error-prone relative to nontransformed cells. Neuroblastoma cells derived from tumorigenic neuroblastic phenotypes had differential DNA repair protein expression patterns compared with nontumorigenic cells. Tumorigenic neuroblastoma cells were deficient in DNA ligase IV (Lig4) and Artemis (DCLRE1C), mediators of canonical NHEJ. Conversely, enzymes required for an error-prone alternative NHEJ pathway (alt-NHEJ), DNA Ligase IIIα (Lig3), DNA Ligase I (Lig1), and PARP1 protein were upregulated. Inhibition of Lig3 and Lig1 led to DSB accumulation and cell death, linking alt-NHEJ to cell survival in neuroblastoma. Neuroblastoma cells demonstrated sensitivity to PARP1 inhibition (PARPi) that paralleled PARP1 expression. In a dataset of human neuroblastoma patient tumors, overexpression of genes encoding alt-NHEJ proteins associated with poor survival. These findings provide an insight into DNA repair fidelity in neuroblastoma and identify components of the alt-NHEJ pathway as promising therapeutic targets.

Influence of segmental chromosome abnormalities on survival in children over the age of 12 months with unresectable localised peripheral neuroblastic tumours without MYCN amplification.

Background:The prognostic impact of segmental chromosome alterations (SCAs) in children older than 1 year, diagnosed with localised unresectable neuroblastoma (NB) without MYCN amplification enrolled in the European Unresectable Neuroblastoma (EUNB) protocol is still to be clarified, while, for other group of patients, the presence of SCAs is associated with poor prognosis.Methods:To understand the role of SCAs we performed multilocus/pangenomic analysis of 98 tumour samples from patients enrolled in the EUNB protocol.Results:Age at diagnosis was categorised into two groups using 18 months as the age cutoff. Significant difference in the presence of SCAs was seen in tumours of patients between 12 and 18 months and over 18 months of age at diagnosis, respectively (P=0.04). A significant correlation (P=0.03) was observed between number of SCAs per tumour and age. Event-free (EFS) and overall survival (OS) were calculated in both age groups, according to both the presence and number of SCAs. In older patients, a poorer survival was associated with the presence of SCAs (EFS=46% vs 75%, P=0.023; OS=66.8% vs 100%, P=0.003). Moreover, OS of older patients inversely correlated with number of SCAs (P=0.002). Finally, SCAs provided additional prognostic information beyond histoprognosis, as their presence was associated with poorer OS in patients over 18 months with unfavourable International Neuroblastoma Pathology Classification (INPC) histopathology (P=0.018).Conclusions:The presence of SCAs is a negative prognostic marker that impairs outcome of patients over the age of 18 months with localised unresectable NB without MYCN amplification, especially when more than one SCA is present. Moreover, in older patients with unfavourable INPC tumour histoprognosis, the presence of SCAs significantly affects OS.