Chromosome 1p and 11q deletions and outcome in neuroblastoma

Long-term survival outcomes of pediatric adrenal malignancies: An analysis with the upstaged SEER registry during 2000-2019

OBJECTIVE

To investigate the clinicopathological characteristics and long-term survival outcomes of pediatric adrenal malignancies.

METHOD

This study retrospectively analyzed children with pathologically confirmed pediatric adrenal malignancies from Surveillance, Epidemiology, and End Results Database from 2000 to 2019. Kaplan-Meier curve was used to assess the overall survival (OS) and cancer-special survival (CSS), and the Log-Rank method was used to calculate statistical differences. Cox proportional hazards model and Fine-and-Grey model were used to calculate the hazard ratio (HR) of all-cause mortality risk and the sub-distribution HR (sHR) of disease-specific mortality risk, respectively, and their corresponding 95% confidence intervals (CI).

RESULTS

1601 children were included in the study in which 1335 (83.4%) neuroblastoma, 151 (9.4%) ganglioneuroblastoma, 89 (5.6%) adrenocortical carcinoma, and 26 (1.6%) were diagnosed with other types malignancies. Metastatic disease accounted for the largest proportion (69.3%), and the proportion of metastases diagnosed by neuroblastoma was higher than that of adrenocortical carcinoma and ganglioneuroblastoma (73.9% vs. 45.7% vs. 47.2%). The 5-year OS and CSS of all cohort were 69.5% and 70.5%, respectively. Adrenal cortical carcinoma had the worst prognosis, with 5-year OS and CSS of 52.5% and 53.1%, respectively. Patients in recent years had no better OS and CSS than in previous years at diagnosis. The tumor stage remained the main prognostic predictor. Compared to metastatic adrenal tumors, the risk of all-cause mortality (adjusted HR: 0.12, 95% CI: 0.06-0.25, P < 0.001) and the risk of disease-specific mortality (adjusted sHR: 0.11, 95% CI: 0.05-0.25, P<0.001) was significantly lower for patients with localized diseases. Additionally, higher age, adrenal cortical carcinoma, and lack of complete tumor resection are independent risk factors for poor prognosis. Furthermore, it was found that the prognosis of patients who received chemotherapy was worse than those who did not, mainly because the former mostly had metastasis at the presentation and complete resection of the tumor cannot be achieved.

CONCLUSION

The clinicopathological characteristics of pediatric adrenal malignancies have not changed significantly in the past two decades, while the prognosis of patients has improved. Early diagnosis of disease and complete resection of local tumors are the keys to improving prognosis.

Impact of 11q Loss of Heterozygosity Status on the Response of High-Risk Neuroblastoma With MYCN Amplification to Neoadjuvant Chemotherapy

PURPOSE

The aim of this study was to investigate whether 11q loss of heterozygosity (LOH) aberration would impact the response of the primary tumor to neoadjuvant chemotherapy or to the degree of surgical resection in neuroblastoma (NB) patients with MYCN amplification.

METHODS

The clinical data of 42 NB patients with MYCN amplification who were newly diagnosed and received treatments at our hospital from 2011 to 2020 were retrospectively analyzed. According to the results of the segmental chromosome aberration analysis, the patients enrolled were assigned to an 11qLOH positive group and an 11qLOH negative group.

RESULTS

There was no significant difference in the mean number of chemotherapy courses completed before surgery between the 11qLOH positive and 11qLOH negative groups (p = 0.242). Each of the 42 patients had metaiodobenzylguanidine (MIBG) scans both before and after neoadjuvant chemotherapy. The percentage of patients who had a clinical MIBG change in the 11qLOH positive group was lower than the percentage in the 11qLOH negative group (27.27 vs. 66.67%, p = 0.030). The 11qLOH negative group seemed to have a higher rate of surgical resection (≥90%); however, the difference between the two groups was not statistically significant (p = 0.088). Furthermore, the 11qLOH negative group did not show significantly superior event-free survival and overall survival rates compared with the 11qLOH positive group.

CONCLUSIONS

This study showed that patients with NB and MYCN amplification in combination with 11qLOH might be less likely to respond to neoadjuvant chemotherapy when compared with patients with NB and MYCN amplification without 11qLOH.

Retrospective Analysis of INRG Clinical and Genomic Factors for 605 Neuroblastomas in Japan: A Report from the Japan Children’s Cancer Group Neuroblastoma Committee (JCCG-JNBSG)

Neuroblastomas (NBs) exhibit broad and divergent clinical behaviors and tumor risk classification at diagnosis is crucial for the selection of an appropriate therapeutic strategy for each patient. The present study aimed to validate the clinical relevance of International Neuroblastoma Risk Group (INRG) prognostic and genomic markers in a Japanese NB cohort using a retrospective analysis. Follow-up data based on 30 common INRG queries in 605 NB cases diagnosed in Japan between 1990 and 2014 were collected and the genome signature of each tumor sample was integrated. As previously indicated, age, tumor stage, MYCN, DNA ploidy, the adrenals as the primary tumor site, serum ferritin and lactate dehydrogenase (LDH) levels, segmental chromosome aberrations, and the number of chromosome breakpoints (BP) correlated with lower survival rates, while the thorax as the primary tumor site and numerical chromosome aberrations correlated with a favorable prognosis. In the patient group with stage 4, MYCN non-amplified tumors (n = 225), one of the challenging subsets for risk stratification, age ≥ 18 months, LDH ≥ 1400 U/L, and BP ≥ 7 correlated with lower overall and event-free survival rates (p < 0.05). The genome subgroup GG-P2s (partial chromosome gain/loss type with 1p/11q losses and 17q gain, n = 30) was strongly associated with a lower overall survival rate (5-year survival rate: 34%, p < 0.05). Therefore, the combination of the tumor genomic pattern (GG-P2s and BP ≥ 7) with age at diagnosis and LDH will be a promising predictor for MYCN-non-amplified high-risk NBs in patient subsets, in accordance with previous findings from the INRG project.

Chromosome Imbalances in Neuroblastoma-Recent Molecular Insight into Chromosome 1p-deletion, 2p-gain, and 11q-deletion Identifies New Friends and Foes for the Future

Simple Summary

Neuroblastoma is a pediatric cancer that arises in the sympathetic nervous system. High-risk neuroblastoma is clinically challenging and identification of novel therapies, particularly those that offer a reduction in morbidity for these patients, is a high priority. Combining genetic analyses with investigation of molecular mechanisms, while considering recent advances in our understanding of key developmental events, provides avenues for future treatment. Here we review and highlight several recently published articles that address novel molecular mechanisms arising from chromosome 1p, 2p, and 11q aberrations, which likely contribute to high-risk neuroblastoma, and discusses their potential impact on treatment options.

Abstract

Neuroblastoma is the most common extracranial solid pediatric tumor, with around 15% childhood cancer-related mortality. High-risk neuroblastomas exhibit a range of genetic, morphological, and clinical heterogeneities, which add complexity to diagnosis and treatment with existing modalities. Identification of novel therapies is a high priority in high-risk neuroblastoma, and the combination of genetic analysis with increased mechanistic understanding—including identification of key signaling and developmental events—provides optimism for the future. This focused review highlights several recent findings concerning chromosomes 1p, 2p, and 11q, which link genetic aberrations with aberrant molecular signaling output. These novel molecular insights contribute important knowledge towards more effective treatment strategies for neuroblastoma.

ATR inhibition enables complete tumour regression in ALK-driven NB mouse models

High-risk neuroblastoma (NB) often involves MYCN amplification as well as mutations in ALK. Currently, high-risk NB presents significant clinical challenges, and additional therapeutic options are needed. Oncogenes like MYCN and ALK result in increased replication stress in cancer cells, offering therapeutically exploitable options. We have pursued phosphoproteomic analyses highlighting ATR activity in ALK-driven NB cells, identifying the BAY1895344 ATR inhibitor as a potent inhibitor of NB cell growth and proliferation. Using RNA-Seq, proteomics and phosphoproteomics we characterize NB cell and tumour responses to ATR inhibition, identifying key components of the DNA damage response as ATR targets in NB cells. ATR inhibition also produces robust responses in mouse models. Remarkably, a 2-week combined ATR/ALK inhibition protocol leads to complete tumor regression in two independent genetically modified mouse NB models. These results suggest that NB patients, particularly in high-risk groups with oncogene-induced replication stress, may benefit from ATR inhibition as therapeutic intervention.

Effective therapeutic options are still needed in neuroblastoma treatment. Here, the authors, through a comprehensive proteomics analysis, identify ATR as a potential therapeutic target of neuroblastoma and demonstrate the efficacy of the ATR inhibitor BAY1895344 in combination with the ALK tyrosine kinase inhibitor lorlatinib.

Spatial and temporal intratumour heterogeneity has potential consequences for single biopsy-based neuroblastoma treatment decisions

Intratumour heterogeneity is a major cause of treatment failure in cancer. We present in-depth analyses combining transcriptomic and genomic profiling with ultra-deep targeted sequencing of multiregional biopsies in 10 patients with neuroblastoma, a devastating childhood tumour. We observe high spatial and temporal heterogeneity in somatic mutations and somatic copy-number alterations which are reflected on the transcriptomic level. Mutations in some druggable target genes including ALK and FGFR1 are heterogeneous at diagnosis and/or relapse, raising the issue whether current target prioritization and molecular risk stratification procedures in single biopsies are sufficiently reliable for therapy decisions. The genetic heterogeneity in gene mutations and chromosome aberrations observed in deep analyses from patient courses suggest clonal evolution before treatment and under treatment pressure, and support early emergence of metastatic clones and ongoing chromosomal instability during disease evolution. We report continuous clonal evolution on mutational and copy number levels in neuroblastoma, and detail its implications for therapy selection, risk stratification and therapy resistance.

FGFR2 loss sensitizes MYCN-amplified neuroblastoma CHP134 cells to CHK1 inhibitor-induced apoptosis

Checkpoint kinase 1 (CHK1) plays a key role in genome surveillance and integrity throughout the cell cycle. Selective inhibitors of CHK1 (CHK1i) are undergoing clinical evaluation for various human malignancies, including neuroblastoma. In this study, one CHK1i‐sensitive neuroblastoma cell line, CHP134, was investigated, which characteristically carries MYCN amplification and a chromosome deletion within the 10q region. Among several cancer‐related genes in the chromosome 10q region, mRNA expression of fibroblast growth factor receptor 2 (FGFR2) was altered in CHP134 cells and associated with an unfavorable prognosis of patients with neuroblastoma. Induced expression of FGFR2 in CHP134 cells reactivated downstream MEK/ERK signaling and resulted in cells resistant to CHK1i‐mediated cell growth inhibition. Consistently, the MEK1/2 inhibitor, trametinib, potentiated CHK1 inhibitor–mediated cell death in these cells. These results suggested that FGFR2 loss might be prone to highly effective CHK1i treatment. In conclusion, extreme cellular dependency of ERK activation may imply a possible application for the MEK1/2 inhibitor, either as a single inhibitor or in combination with CHK1i in MYCN‐amplified neuroblastomas.

Molecular Basis and Clinical Features of Neuroblastoma

Neuroblastoma, a neoplasm of the sympathetic nervous system, originates from neuroblastoma stem cells during embryogenesis. It exhibits unique clinical features including a tendency for spontaneous regression of tumors in infants and a high frequency of metastatic disease at diagnosis in patients aged over 18 months. Genetic risk factors and epigenetic dysregulation also play a significant role in the development of neuroblastoma. Over the past decade, our understanding of this disease has advanced considerably. This has included the identification of chromosomal copy number aberrations specific to neuroblastoma development, risk groups, and disease stage. However, high-risk neuroblastoma remains a therapeutic challenge for pediatric oncologists. New therapeutic approaches have been developed, either as alternatives to conventional chemotherapy or in combination, to overcome the dismal prognosis. Particularly promising strategies are targeted therapies that directly affect cancer cells or cancer stem cells while exhibiting minimal effect on healthy cells. This review summarizes our understanding of neuroblastoma biology and prognostic features and focuses on novel therapeutic strategies for this intractable disease.

Neuroblastoma-Telomere maintenance, deregulated signaling transduction and beyond

The childhood malignancy neuroblastoma belongs to the group of embryonal tumors and originates from progenitor cells of the sympathoadrenal lineage. Treatment options for children with high-risk and relapsed disease are still very limited. In recent years, an ever-growing molecular diversity was identified using (epi)-genetic profiling of neuroblastoma tumors, indicating that molecularly targeted therapies could be a promising therapeutic option. In this review article, we summarize the various molecular subtypes and genetic events associated with neuroblastoma and describe recent advances in targeted therapies. We lay a strong emphasis on the importance of telomere maintenance mechanisms for understanding tumor progression and risk classification of neuroblastoma.

Revised Neuroblastoma Risk Classification System: A Report From the Children's Oncology Group

PURPOSE

Treatment planning for children with neuroblastoma requires accurate assessment of prognosis. The most recent Children's Oncology Group (COG) risk classification system used tumor stage as defined by the International Neuroblastoma Staging System. Here, we validate a revised classifier using the International Neuroblastoma Risk Group Staging System (INRGSS) and incorporate segmental chromosome aberrations (SCA) as an additional genomic biomarker.

METHODS

Newly diagnosed patients enrolled on the COG neuroblastoma biology study ANBL00B1 between 2007 and 2017 with known age, International Neuroblastoma Staging System, and INRGSS stage were identified (N = 4,832). Tumor MYCN status, ploidy, SCA status (1p and 11q), and International Neuroblastoma Pathology Classification histology were determined centrally. Survival analyses were performed for combinations of prognostic factors used in COG risk classification according to the prior version 1, and to validate a revised algorithm (version 2).

RESULTS

Most patients with locoregional tumors had excellent outcomes except for those with image-defined risk factors (INRGSS L2) with MYCN amplification (5-year event-free survival and overall survival: 76.3% ± 5.8% and 79.9% ± 5.5%, respectively) or patients age ≥ 18 months with L2 MYCN nonamplified tumors with unfavorable International Neuroblastoma Pathology Classification histology (72.7% ± 5.4% and 82.4% ± 4.6%), which includes the majority of L2 patients with SCA. For patients with stage M (metastatic) and MS (metastatic, special) disease, genomic biomarkers affected risk group assignment for those < 12 months (MYCN) or 12-18 months (MYCN, histology, ploidy, and SCA) of age. In a retrospective analysis of patient outcome, the 5-year event-free survival and overall survival using COG version 1 were low-risk: 89.4% ± 1.1% and 97.9% ± 0.5%; intermediate-risk: 86.1% ± 1.3% and 94.9% ± 0.8%; high-risk: 50.8% ± 1.4% and 61.9% ± 1.3%; and using COG version 2 were low-risk: 90.7% ± 1.1% and 97.9% ± 0.5%; intermediate-risk: 85.1% ± 1.4% and 95.8% ± 0.8%; high-risk: 51.2% ± 1.4% and 62.5% ± 1.3%, respectively.

CONCLUSION

A revised 2021 COG neuroblastoma risk classifier (version 2) that uses the INRGSS and incorporates SCAs has been adopted to prospectively define COG clinical trial eligibility and treatment assignment.

Integrated CGH/WES Analyses Advance Understanding of Aggressive Neuroblastoma Evolution: A Case Study

Neuroblastoma (NB) is the most common extra-cranial malignancy in preschool children. To portray the genetic landscape of an overly aggressive NB leading to a rapid clinical progression of the disease, tumor DNA collected pre- and post-treatment has been analyzed. Array comparative genomic hybridization (aCGH), whole-exome sequencing (WES), and pharmacogenetics approaches, respectively, have identified relevant copy number alterations (CNAs), single nucleotide variants (SNVs), and polymorphisms (SNPs) that were then combined into an integrated analysis. Spontaneously formed 3D tumoroids obtained from the recurrent mass have also been characterized. The results prove the power of combining CNAs, SNVs, and SNPs analyses to assess clonal evolution during the disease progression by evidencing multiple clones at disease onset and dynamic genomic alterations during therapy administration. The proposed molecular and cytogenetic integrated analysis empowers the disease follow-up and the prediction of tumor recurrence.

Copy number alteration analysis for neuroblastoma using droplet digital polymerase chain reaction

BACKGROUND

Neuroblastoma (NB) is a malignant tumor derived from the neural crest. MYCN amplification is a well-known adverse molecular prognostic factor for NB. Genome copy number alterations (CNAs) such as chromosome (Chr) 11q deletion, 1p deletion, and 17q gain are associated with a poor prognosis. Fluorescence in situ hybridization (FISH) and Southern blotting analysis are frequently used to detect MYCN amplification. Although comparative genomic hybridization (CGH) and single-nucleotide polymorphism (SNP) chip arrays can easily detect CNAs, these methods are impractical for clinical use due to their cost and run time. Consequently, genome copy number analysis using digital droplet PCR has become widely used to monitor CNAs.

METHODS

In this study, we used digital droplet polymerase chain reaction to detect MYCN amplification and Chr 11q CNA, which was used for risk stratification according to the International Neuroblastoma Risk Group classification system. We compared the results with data from SNP chip arrays in seven NB cell lines and eight primary NB samples.

RESULTS

Digital droplet PCR assays successfully detected MYCN amplification and 11q CNA. The results were very consistent with those obtained by SNP chip assay.

CONCLUSIONS

Digital droplet PCR can be conducted more rapidly than FISH or Southern blotting. Accordingly, it should be useful for on-site clinical applications aimed at detecting CNAs in NB and performing risk stratification promptly after diagnosis.

Neuronal Differentiation-Related Epigenetic Regulator ZRF1 Has Independent Prognostic Value in Neuroblastoma but Is Functionally Dispensable In Vitro

Simple Summary

Neuroblastoma is the most common pediatric solid tumor occurring outside the brain, and it is thought to arise from cells that acquire errors during the normal process of embryonal development. Today, we know that embryonal development is regulated by epigenetics, a mechanism that determines which genes need to be expressed in each cell type and developmental step. Epigenetic errors, therefore, are considered contributory to the appearance and progression of tumors such as neuroblastoma. Here, we aimed at finding whether ZRF1, a known epigenetic regulator, could play a significant role in the aggressiveness of neuroblastoma. Our results suggest that ZRF1 does not seem to have any relevant function in neuroblastoma cells; however, the levels of this epigenetic regulator are related to the prognostic of neuroblastoma patients and could be used to predict their progression and improve the diagnosis.

Abstract

Neuroblastoma is a pediatric tumor of the peripheral nervous system that accounts for up to ~15% of all cancer-related deaths in children. Recently, it has become evident that epigenetic deregulation is a relevant event in pediatric tumors such as high-risk neuroblastomas, and a determinant for processes, such as cell differentiation blockade and sustained proliferation, which promote tumor progression and resistance to current therapies. Thus, a better understanding of epigenetic factors implicated in the aggressive behavior of neuroblastoma cells is crucial for the development of better treatments. In this study, we characterized the role of ZRF1, an epigenetic activator recruited to genes involved in the maintenance of the identity of neural progenitors. We combined analysis of patient sample expression datasets with loss- and gain-of-function studies on neuroblastoma cell lines. Functional analyses revealed that ZRF1 is functionally dispensable for those cellular functions related to cell differentiation, proliferation, migration, and invasion, and does not affect the cellular response to chemotherapeutic agents. However, we found that high levels of ZRF1 mRNA expression are associated to shorter overall survival of neuroblastoma patients, even when those patients with the most common molecular alterations used as prognostic factors are removed from the analyses, thereby suggesting that ZRF1 expression could be used as an independent prognostic factor in neuroblastoma.

Biomarkers in Neuroblastoma: An Insight into Their Potential Diagnostic and Prognostic Utilities

OPINION STATEMENT

Neuroblastoma (NB) is a heterogeneous solid tumor of the pediatric population that originates from neural crest cells and affects the developing sympathetic nervous system. It is the most common neuroblastic tumor accounting for approximately 10% of all childhood cancers and 10-15% of pediatric tumor mortalities. The outcomes range from spontaneous tumor regression in low-risk groups to metastasis and death even after multimodal therapy in high-risk groups. Hence, the detection of NB at an early stage improves outcomes and provides a better prognosis for patients. Early detection and prognosis of NB depend on specific molecules termed biomarkers which can be tissue-specific or circulating. Certain biomarkers are employed in the classification of NB into different groups to improve the treatment and prognosis, and others can be used as therapeutic targets. Therefore, novel biomarker discovery is essential for the early detection of NB, predicting the course of the disease, and developing new targeted treatment strategies. In this review, we aim to summarize the literature pertinent to some important biomarkers of NB and discuss the prognostic role of these biomarkers as well as their potential role in targeted therapy.

Comparison of Next-Generation Sequencing and Fluorescence In Situ Hybridization for Detection of Segmental Chromosomal Aberrations in Neuroblastoma

The aim of this study was to compare next-generation sequencing (NGS) with the traditional fluorescence in situ hybridization (FISH) for detecting segmental chromosomal aberrations (SCAs) such as 1p deletion, 11q deletion and 17q gain, which are well-known predictive markers for adverse outcome in neuroblastoma. The tumor tissue obtained from 35 patients with neuroblastoma was tested by FISH and targeted NGS, which is specially designed to detect copy number alterations across the entire chromosomal region in addition to mutations in 353 cancer-related genes. All chromosomal copy number alterations were analyzed using the copy number variation plot derived from targeted NGS. FISH was performed to detect 1p deletion, 11q deletion and 17q gain. The copy numbers of 1p, 11q, and 17q obtained via NGS were correlated with those acquired via FISH. The SCAs determined by NGS were matched with those by FISH. Most 17q gain of mismatched cases detected by NGS alone showed a subsegmental gain of 17q. FISH revealed 11q deletion and 17q gain in a few tumor cells of two cases, which were not detected by NGS. NGS can be a sensitive complementary and alternative method to the conventional FISH for detecting SCAs.

Early Decline of Neuron-Specific Enolase during Neuroblastoma Chemotherapy is a Predictive Factor of Clinical Outcome

High risk neuroblastoma (HR-NB) remains one of the most difficult-to-treat pediatric cancers. However, although current risk-stratification is based on multiple pretreatment criteria, HR-NB remains a significant heterogeneity. We examined 60 patients with HR-NB for a median follow-up time of 28 months. We examined the serum neuronspecific enolase (NSE) levels of each chemo cycle, using the survival receiver operating characteristic (survivalROC) method to assess the prognostic power of NSE levels at variant chemo points. We demonstrated that serum NSE was associated with systemic tumor burden. NSE after the third chemo cycle (C3) (C3NSE) was significantly higher in patients who eventually showed cancer relapse or progression. C3NSE had independent prognostic significance for event-free survival (EFS) but not for overall survival (OS) in multivariate cox analysis. SurvivalROC prompted that the C3NSE is a prognostic marker of HR-NB, which had good discrimination for 2- and 3-year EFS with AUC 0.734 and 0.729, respectively. However, its prognositc value for 2- and 3- year OS declined progressively. C3 is the optimal point to predict EFS. Patients whose C3 serum NSE remain at higher level need to undergo more intensive treatment as early as possible to resist recurrence.

Neuroblastoma GD2 Expression and Computational Analysis of Aptamer-Based Bioaffinity Targeting

Neuroblastoma (NB) is a neuroectodermal embryonic cancer that originates from primordial neural crest cells, and amongst pediatric cancers with high mortality rates. NB is categorized into high-, intermediate-, and low-risk cases. A significant proportion of high-risk patients who achieve remission have a minimal residual disease (MRD) that causes relapse. Whilst there exists a myriad of advanced treatment options for NB, it is still characterized by a high relapse rate, resulting in a reduced chance of survival. Disialoganglioside (GD2) is a lipo-ganglioside containing a fatty acid derivative of sphingosine that is coupled to a monosaccharide and a sialic acid. Amongst pediatric solid tumors, NB tumor cells are known to express GD2; hence, it represents a unique antigen for subclinical NB MRD detection and analysis with implications in determining a response for treatment. This article discusses NB MRD expression and analytical assays for GD2 detection and quantification as well as computational approaches for GD2 characterization based on high-throughput image processing and genomic data analysis.

Exceptional response to the ALK and ROS1 inhibitor lorlatinib and subsequent mechanism of resistance in relapsed ALK F1174L-mutated neuroblastoma

Treatment of high-risk neuroblastoma typically incorporates multiagent chemotherapy, surgery, radiation therapy, autologous stem cell transplantation, immunotherapy, and differentiation therapy. The discovery of activating mutations in ALK receptor tyrosine kinase (ALK) in ∼8% of neuroblastomas opens the possibility of further improving outcomes for this subset of patients with the addition of ALK inhibitors. ALK inhibitors have shown efficacy in tumors such as non-small-cell lung cancer and anaplastic large cell lymphoma in which wild-type ALK overexpression is driven by translocation events. In contrast, ALK mutations driving neuroblastomas are missense mutations in the tyrosine kinase domain yielding constitutive activation and differing sensitivity to available ALK inhibitors. We describe a case of a patient with relapsed, refractory, metastatic ALK F1174L-mutated neuroblastoma who showed no response to the first-generation ALK inhibitor crizotinib but had a subsequent complete response to the ALK/ROS1 inhibitor lorlatinib. The patient's disease relapsed after 13 mo of treatment. Sequencing of cell-free DNA at the time of relapse pointed toward a potential mechanism of acquired lorlatinib resistance: amplification of CDK4 and FGFR1 and a NRAS Q61K mutation. We review the literature regarding differing sensitivity of ALK mutations found in neuroblastoma to current FDA-approved ALK inhibitors and known pathways of acquired resistance. Our report adds to the literature of important correlations between neuroblastoma ALK mutation status and clinical responsiveness to ALK inhibitors. It also highlights the importance of understanding acquired mechanisms of resistance.

How Do Telomere Abnormalities Regulate the Biology of Neuroblastoma?

Telomere maintenance plays important roles in genome stability and cell proliferation. Tumor cells acquire replicative immortality by activating a telomere-maintenance mechanism (TMM), either telomerase, a reverse transcriptase, or the alternative lengthening of telomeres (ALT) mechanism. Recent advances in the genetic and molecular characterization of TMM revealed that telomerase activation and ALT define distinct neuroblastoma (NB) subgroups with adverse outcomes, and represent promising therapeutic targets in high-risk neuroblastoma (HRNB), an aggressive childhood solid tumor that accounts for 15% of all pediatric-cancer deaths. Patients with HRNB frequently present with widely metastatic disease, with tumors harboring recurrent genetic aberrations (MYCN amplification, TERT rearrangements, and ATRX mutations), which are mutually exclusive and capable of promoting TMM. This review provides recent insights into our understanding of TMM in NB tumors, and highlights emerging therapeutic strategies as potential treatments for telomerase- and ALT-positive tumors.

Engineering large-scale chromosomal deletions by CRISPR-Cas9

Large-scale chromosomal deletions are a prevalent and defining feature of cancer. A high degree of tumor-type and subtype specific recurrencies suggest a selective oncogenic advantage. However, due to their large size it has been difficult to pinpoint the oncogenic drivers that confer this advantage. Suitable functional genomics approaches to study the oncogenic driving capacity of large-scale deletions are limited. Here, we present an effective technique to engineer large-scale deletions by CRISPR-Cas9 and create isogenic cell line models. We simultaneously induce double-strand breaks (DSBs) at two ends of a chromosomal arm and select the cells that have lost the intermittent region. Using this technique, we induced large-scale deletions on chromosome 11q (65 Mb) and chromosome 6q (53 Mb) in neuroblastoma cell lines. A high frequency of successful deletions (up to 30% of selected clones) and increased colony forming capacity in the 11q deleted lines suggest an oncogenic advantage of these deletions. Such isogenic models enable further research on the role of large-scale deletions in tumor development and growth, and their possible therapeutic potential.

Mediastinal neuroblastoma, ganglioneuroblastoma, and ganglioneuroma: Pathology review and diagnostic approach

Neuroblastic tumors are a group of tumors of the sympathetic ganglia and adrenal medulla that derive from primordial neural crest cells. These tumors include neuroblastoma, intermixed ganglioneuroblastoma, nodular ganglioneuroblastoma, and ganglioneuroma. Neuroblastomas are the most common extracranial solid tumor arising in childhood and may occur in different anatomic sites. Neuroblastic tumors are common mesenchymal tumors of the mediastinum. Herein, we describe advances in our understanding of neuroblastic tumor biology. Pathologists should be aware of diagnostic challenges associated with these tumors to ensure correct histologic diagnosis and appropriate clinical management. We describe updated mediastinal neuroblastic tumor pathology, focusing on morphological, immunohistochemical, and molecular features and differential diagnoses.

Non-Genomic Control of Dynamic MYCN Gene Expression in Liver Cancer

Upregulated MYCN gene expression is restricted to specialized cell populations such as EpCAM⁺ cancer stem cells in liver cancer, regardless of DNA amplification and mutation. Here, we reviewed the role of MYCN gene expression in liver homeostasis, regeneration, and tumorigenesis, and discussed the potential non-genomic mechanisms involved in controlling MYCN gene expression in liver cancer, with a focus on inflammation-mediated signal transduction and microRNA-associated post-transcriptional regulation. We concluded that dynamic MYCN gene expression is an integrated consequence of multiple signals in the tumor microenvironment, including tumor growth-promoting signals, lipid desaturation-mediated endoplasmic reticulum stress adaptation signals, and tumor suppressive miRNAs, making it a potential predictive biomarker of tumor stemness and plasticity. Therefore, understanding and tracing the dynamic changes and functions of MYCN gene expression will shed light on the origin of liver tumorigenesis at the cellular level and the development of novel therapeutic and diagnostic strategies for liver cancer treatment.

Management of Neuroblastoma in Pediatric Patients

Surgeons caring for patients with neuroblastoma must be familiar with recent developments in assessing risk. In particular, the Children's Oncology Group, along with major international groups, uses the International Neuroblastoma Risk Group Staging System as a risk assessment tool. Accurate risk determination is essential for optimal surgical therapy. Some tumors like neonatal adrenal neuroblastomas and those in the metastatic category can be observed. Very-low-risk and low-risk neuroblastomas can be treated with surgery alone. Intermediate-risk tumors also often require systemic chemotherapy.

Neonatal Neuroblastoma

Neuroblastoma accounts for approximately 8% of all pediatric cancers, with 5% diagnosed during the neonatal period. Despite the disproportionate contribution of neuroblastoma to childhood cancer deaths, neonatal neuroblastoma has a favorable prognosis, often with little or no therapy required. Therefore, minimizing therapy and mitigating complications/toxicities are emphasized, including using a watch-and-wait approach for patients at low risk for disease progression/relapse. However, stage MS neuroblastoma exhibits a unique pattern of disseminated disease, can be challenging to manage, and may require early intervention with systemic chemotherapy. In this review, the epidemiology, treatment options, and anticipated outcomes for neonatal neuroblastoma are discussed.

Neuroblastoma and the epigenome

Neuroblastoma (NB) is a pediatric cancer of the sympathetic nervous system and one of the most common solid tumors in infancy. Amplification of MYCN, copy number alterations, numerical and segmental chromosomal aberrations, mutations, and rearrangements on a handful of genes, such as ALK, ATRX, TP53, RAS/MAPK pathway genes, and TERT, are attributed as underlying causes that give rise to NB. However, the heterogeneous nature of the disease-along with the relative paucity of recurrent somatic mutations-reinforces the need to understand the interplay of genetic factors and epigenetic alterations in the context of NB. Epigenetic mechanisms tightly control gene expression, embryogenesis, imprinting, chromosomal stability, and tumorigenesis, thereby playing a pivotal role in physio- and pathological settings. The main epigenetic alterations include aberrant DNA methylation, disrupted patterns of posttranslational histone modifications, alterations in chromatin composition and/or architecture, and aberrant expression of non-coding RNAs. DNA methylation and demethylation are mediated by DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) proteins, respectively, while histone modifications are coordinated by histone acetyltransferases and deacetylases (HATs, HDACs), and histone methyltransferases and demethylases (HMTs, HDMs). This article focuses predominately on the crosstalk between the epigenome and NB, and the implications it has on disease diagnosis and treatment.

Alternative lengthening of telomeres in childhood neuroblastoma from genome to proteome

Telomere maintenance by telomerase activation or alternative lengthening of telomeres (ALT) is a major determinant of poor outcome in neuroblastoma. Here, we screen for ALT in primary and relapsed neuroblastomas (n = 760) and characterize its features using multi-omics profiling. ALT-positive tumors are molecularly distinct from other neuroblastoma subtypes and enriched in a population-based clinical sequencing study cohort for relapsed cases. They display reduced ATRX/DAXX complex abundance, due to either ATRX mutations (55%) or low protein expression. The heterochromatic histone mark H3K9me3 recognized by ATRX is enriched at the telomeres of ALT-positive tumors. Notably, we find a high frequency of telomeric repeat loci with a neuroblastoma ALT-specific hotspot on chr1q42.2 and loss of the adjacent chromosomal segment forming a neo-telomere. ALT-positive neuroblastomas proliferate slowly, which is reflected by a protracted clinical course of disease. Nevertheless, children with an ALT-positive neuroblastoma have dismal outcome.

Recurrent Somatic Chromosomal Abnormalities in Relapsed Extraocular Retinoblastoma

Simple Summary

Relapse outside the eye of retinoblastoma (the most common eye cancer in children) is an uncommon event in developed countries, however it is the main cause of death in patients with retinoblastoma worldwide. The genomic features of this population are not known. We studied 23 cases from four countries and found a characteristic pattern in chromosomal copy number alterations that could help guide future clinical management of these patients.

Abstract

Most reports about copy number alterations (CNA) in retinoblastoma relate to patients with intraocular disease and features of children with extraocular relapse remain unknown, so we aimed to describe the CNA in this population. We evaluated 23 patients and 27 specimens from 4 centers. Seventeen cases had extraocular relapse after initial enucleation and six cases after an initial preservation attempt. We performed an analysis of CNA and BCOR gene alteration by SNP array (Single Nucleotide Polymorfism array), whole-exome sequencing, IMPACT panel and CGH array (Array-based comparative genomic hybridization). All cases presented CNA at a higher prevalence than those reported in previously published studies for intraocular cases. CNA previously reported for intraocular retinoblastoma were found at a high frequency in our cohort: gains in 1q (69.5%), 2p (60.9%) and 6p (86.9%), and 16q loss (78.2%). Other, previously less-recognized, CNA were found including loss of 11q (34.8%), gain of 17q (56.5%), loss of 19q (30.4%) and BCOR alterations were present in 72.7% of our cases. A high number of CNA including 11q deletions, 17q gains, 19q loss, and BCOR alterations, are more common in extraocular retinoblastoma. Identification of these features may be correlated with a more aggressive tumor warranting consideration for patient management.

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

Simple Summary

Neuroblastoma, 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.

Abstract

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Intratumoral immunosuppression profiles in 11q-deleted neuroblastomas provide new potential therapeutic targets

High‐risk neuroblastoma (NB) patients with 11q deletion frequently undergo late but consecutive relapse cycles with fatal outcome. To date, no actionable targets to improve current multimodal treatment have been identified. We analyzed immune microenvironment and genetic profiles of high‐risk NB correlating with 11q immune status. We show in two independent cohorts that 11q‐deleted NB exhibits various immune inhibitory mechanisms, including increased CD4+ resting T cells and M2 macrophages, higher expression of programmed death‐ligand 1, interleukin‐10, transforming growth factor‐beta‐1, and indoleamine 2,3‐dioxygenase 1 (P < 0.05), and also higher chromosomal breakages (P ≤ 0.02) and hemizygosity of immunosuppressive miRNAs than MYCN‐amplified and other 11q‐nondeleted high‐risk NB. We also analyzed benefits of maintenance treatment in 83 high‐risk stage M NB patients focusing on 11q status, either with standard anti‐GD2 immunotherapy (n = 50) or previous retinoic acid‐based therapy alone (n = 33). Immunotherapy associated with higher EFS (50 vs. 30, P = 0.028) and OS (72 vs. 52, P = 0.047) at 3 years in the overall population. Despite benefits from standard anti‐GD2 immunotherapy in high‐risk NB patients, those with 11q deletion still face poor outcome. This NB subgroup displays intratumoral immune suppression profiles, revealing a potential therapeutic strategy with combination immunotherapy to circumvent this immune checkpoint blockade.

Association of high-risk neuroblastoma classification based on expression profiles with differentiation and metabolism

Neuroblastoma, the most common extracranial solid malignancy among children, originates from undifferentiated neural crest cells (NCC). Despite recent intensified treatment, high-risk patients still have a high mortality rate. To explore a new therapeutic strategy, we performed an integrated genomic and transcriptomic analysis of 30 high-risk neuroblastoma cases. Based on the expression profiling of RNA sequencing, neuroblastoma was classified into Mesenchymal (MES; n = 5) and Noradrenergic (ADRN; n = 25) clusters, as previously reported in the super-enhancer landscape. The expression patterns in MES-cluster cases were similar to normal adrenal glands, with enrichment in secretion-related pathways, suggesting chromaffin cell-like features built from NCC-derived Schwann cell precursors (SCPs). In contrast, neuron-related pathways were enriched in the ADRN-cluster, indicating sympathoblast features reported to originate from NCC but not via SCPs. Thus, MES- and ADRN-clusters were assumed to be corresponding to differentiation pathways through SCP and sympathoblast, respectively. ADRN-cluster cases were further classified into MYCN- and ATRX-clusters, characterized by genetic alterations, MYCN amplifications and ATRX alterations, respectively. MYCN-cluster cases showed high expression of ALDH18A1, encoding P5CS related to proline production. As reported in other cancers, this might cause reprogramming of proline metabolism leading to tumor specific proline vulnerability candidate for a target therapy of metabolic pathway. In ATRX-cluster, SLC18A2 (VMAT2), an enzyme known to prevent cell toxicity due to the oxidation of dopamine, was highly expressed and VMAT2 inhibitor (GZ-793A) represented significant attenuation of cell growth in NB-69 cell line (high SLC18A2 expression, no MYCN amplification) but not in IMR-32 cell line (MYCN amplification). In addition, the correlation of VMAT2 expression with metaiodobenzylguanidine (MIBG) avidity suggested a combination of VMAT2 inhibitor and MIBG radiation for a novel potential therapeutic strategy in ATRX-cluster cases. Thus, targeting the characteristics of unique neuroblastomas may prospectively improve prognosis.

Targeting Loss of Heterozygosity: A Novel Paradigm for Cancer Therapy

Loss of heterozygosity (LOH) is a common genetic event in the development of cancer. In certain tumor types, LOH can affect more than 20% of the genome, entailing loss of allelic variation in thousands of genes. This reduction of heterozygosity creates genetic differences between tumor and normal cells, providing opportunities for development of novel cancer therapies. Here, we review and summarize (1) mutations associated with LOH on chromosomes which have been shown to be promising biomarkers of cancer risk or the prediction of clinical outcomes in certain types of tumors; (2) loci undergoing LOH that can be targeted for development of novel anticancer drugs as well as (3) LOH in tumors provides up-and-coming possibilities to understand the underlying mechanisms of cancer evolution and to discover novel cancer vulnerabilities which are worth a further investigation in the near future.

Refining immunotherapeutic approaches to high-risk neuroblastoma based on tumor genomic profiles

In this issue, Coronado et al. attempt to improve our understanding of the factors affecting the response to immunotherapy in a large subset of high‐risk neuroblastoma with hemizygous deletion of chromosome 11q. By using several computational approaches, the authors study potential transcriptional and post‐transcriptional pathways that may affect the response to immunotherapy and further be leveraged therapeutically in a biomarker‐directed fashion.

Association of image-defined risk factors with clinical features, histopathology, and outcomes in neuroblastoma

BACKGROUND

Clinical, molecular, and histopathologic features guide treatment for neuroblastoma, but obtaining tumor tissue may cause complications and is subject to sampling error due to tumor heterogeneity. We hypothesized that image-defined risk factors (IDRFs) would reflect molecular features, histopathology, and clinical outcomes in neuroblastoma.

METHODS

We performed a retrospective cohort study of 76 patients with neuroblastoma or ganglioneuroblastoma. Diagnostic CT scans were reviewed for 20 IDRFs, which were consolidated into five IDRF groups (involvement of multiple body compartments, vascular encasement, tumor infiltration of adjacent organs/structures, airway compression, or intraspinal extension). IDRF groups were analyzed for association with clinical, molecular, and histopathologic features of neuroblastoma.

RESULTS

Patients with more IDRF groups had a higher risk of surgical complications (OR = 3.1, p = 0.001). Tumor vascular encasement was associated with increased risk of surgical complications (OR = 5.40, p = 0.009) and increased risk of undifferentiated/poorly differentiated histologic grade (OR = 11.11, p = 0.013). Tumor infiltration of adjacent organs and structures was associated with decreased survival (HR = 8.90, p = 0.007), MYCN amplification (OR = 9.91, p = 0.001), high MKI (OR = 6.20, p = 0.003), and increased risk of International Neuroblastoma Staging System stage 4 disease (OR = 8.96, p < 0.001).

CONCLUSIONS

The presence of IDRFs at diagnosis was associated with high-risk clinical, molecular, and histopathologic features of neuroblastoma. The IDRF group tumor infiltration into adjacent organs and structures was associated with decreased survival. Collectively, these findings may assist surgical planning and medical management for neuroblastoma patients.

An overview of neuroblastoma cell lineage phenotypes and in vitro models

This review was conducted to present the main neuroblastoma (NB) clinical characteristics and the most common genetic alterations present in these pediatric tumors, highlighting their impact in tumor cell aggressiveness behavior, including metastatic development and treatment resistance, and patients' prognosis. The distinct three NB cell lineage phenotypes, S-type, N-type, and I-type, which are characterized by unique cell surface markers and gene expression patterns, are also reviewed. Finally, an overview of the most used NB cell lines currently available for in vitro studies and their unique cellular and molecular characteristics, which should be taken into account for the selection of the most appropriate model for NB pre-clinical studies, is presented. These valuable models can be complemented by the generation of NB reprogrammed tumor cells or organoids, derived directly from patients' tumor specimens, in the direction toward personalized medicine.

Imbalance between genomic gain and loss identifies high-risk neuroblastoma patients with worse outcomes

Survival in high-risk neuroblastoma (HR-NB) patients remains poor despite multimodal treatment. We aimed to identify HR-NB patients with worse outcomes by analyzing the genomic instability derived from segmental chromosomal aberrations. We calculated 3 genomic instability indexes for primary tumor SNP array profiles from 127 HR-NB patients: (1) Copy number aberration burden (%gains_length+%losses_length), (2) copy number load (CNL) (%gains_length-%losses_length) and (3) net genomic load (NGL) (%gains_amount-%losses_amount). Tumors were classified according to positive or negative CNL and NGL genomic subtypes. The impact of the genomic instability indexes on overall survival (OS) was assessed with Cox regression. We identified 38% of HR-NB patients with poor 5-year OS. A negative CNL genomic background was related to poor prognosis in patients ≥18 months showing tumors with homogeneous MYCN amplification (9.5% survival probability, P < 0.05) and patients with non-MYCN amplified NB (18.8% survival probability related to >2.4% CNL, P < 0.01). A positive CNL genomic background was associated with worse outcome in patients with heterogeneous MYCN amplification (22.5% survival probability, P < 0.05). We conclude that characterizing a tumor genomic background according to predominance of genome gained or lost contributes toward improved outcome prediction and brings greater insight into the tumor biology of HR-NB patients.

Single-Cell Characterization of Malignant Phenotypes and Developmental Trajectories of Adrenal Neuroblastoma

Neuroblastoma (NB), which is a subtype of neural-crest-derived malignancy, is the most common extracranial solid tumor occurring in childhood. Despite extensive research, the underlying developmental origin of NB remains unclear. Using single-cell RNA sequencing, we generate transcriptomes of adrenal NB from 160,910 cells of 16 patients and transcriptomes of putative developmental cells of origin of NB from 12,103 cells of early human embryos and fetal adrenal glands at relatively late development stages. We find that most adrenal NB tumor cells transcriptionally mirror noradrenergic chromaffin cells. Malignant states also recapitulate the proliferation/differentiation status of chromaffin cells in the process of normal development. Our findings provide insight into developmental trajectories and cellular states underlying human initiation and progression of NB.

Molecular targeting therapies for neuroblastoma: Progress and challenges

There is an urgent need to identify novel therapies for childhood cancers. Neuroblastoma is the most common pediatric solid tumor, and accounts for ~15% of childhood cancer‐related mortality. Neuroblastomas exhibit genetic, morphological and clinical heterogeneity, which limits the efficacy of existing treatment modalities. Gaining detailed knowledge of the molecular signatures and genetic variations involved in the pathogenesis of neuroblastoma is necessary to develop safer and more effective treatments for this devastating disease. Recent studies with advanced high‐throughput “omics” techniques have revealed numerous genetic/genomic alterations and dysfunctional pathways that drive the onset, growth, progression, and resistance of neuroblastoma to therapy. A variety of molecular signatures are being evaluated to better understand the disease, with many of them being used as targets to develop new treatments for neuroblastoma patients. In this review, we have summarized the contemporary understanding of the molecular pathways and genetic aberrations, such as those in MYCN, BIRC5, PHOX2B, and LIN28B, involved in the pathogenesis of neuroblastoma, and provide a comprehensive overview of the molecular targeted therapies under preclinical and clinical investigations, particularly those targeting ALK signaling, MDM2, PI3K/Akt/mTOR and RAS‐MAPK pathways, as well as epigenetic regulators. We also give insights on the use of combination therapies involving novel agents that target various pathways. Further, we discuss the future directions that would help identify novel targets and therapeutics and improve the currently available therapies, enhancing the treatment outcomes and survival of patients with neuroblastoma.

Genetic predisposition and chromosome instability in neuroblastoma

Neuroblastoma (NB) is a pediatric tumor of embryonic origin. About 1-2% of all NBs are familial cases, and genetic predisposition is suspected for the remaining cases. During the last decade, genome-wide association studies (GWAS) and high-throughput sequencing approaches have been used to identify associations among common and rare genetic variants and NB risk. Substantial data has been produced by large patient cohorts that implicate various genes in NB tumorigenesis, such as CASC15, BARD1, CHEK2, LMO1, LIN28B, AXIN2, BRCA1, TP53, SMARCA4, and CDK1NB. NB, as well as other pediatric cancers, has few recurrent mutations but several copy number variations (CNVs). Almost all NBs show both numerical and structural CNVs. The proportion between numerical and structural CNVs differs between localized and metastatic tumors, with a greater prevalence of structural CNVs in metastatic NB. This genomic chaos frequently identified in NBs suggests that chromosome instability (CIN) could be one of the major actors in NB oncogenesis. Interestingly, many NB-predisposing variants occur in genes involved in the control of genome stability, mitosis, and normal chromosome separation. Here, we discuss the relationship between genetic predisposition and CIN in NB.

Age Dependency of the Prognostic Impact of Tumor Genomics in Localized Resectable MYCN-Nonamplified Neuroblastomas. Report From the SIOPEN Biology Group on the LNESG Trials and a COG Validation Group

PURPOSE

For localized, resectable neuroblastoma without MYCN amplification, surgery only is recommended even if incomplete. However, it is not known whether the genomic background of these tumors may influence outcome.

PATIENTS AND METHODS

Diagnostic samples were obtained from 317 tumors, International Neuroblastoma Staging System stages 1/2A/2B, from 3 cohorts: Localized Neuroblastoma European Study Group I/II and Children's Oncology Group. Genomic data were analyzed using multi- and pangenomic techniques and fluorescence in-situ hybridization in 2 age groups (cutoff age, 18 months) and were quality controlled by the International Society of Pediatric Oncology European Neuroblastoma (SIOPEN) Biology Group.

RESULTS

Patients with stage 1 tumors had an excellent outcome (5-year event-free survival [EFS] ± standard deviation [SD], 95% ± 2%; 5-year overall survival [OS], 99% ± 1%). In contrast, patients with stage 2 tumors had a reduced EFS in both age groups (5-year EFS ± SD, 84% ± 3% in patients < 18 months of age and 75% ± 7% in patients ≥ 18 months of age). However, OS was significantly decreased only in the latter group (5-year OS ± SD in < 18months and ≥ 18months, 96% ± 2% and 81% ± 7%, respectively; P = .001). In < 18months, relapses occurred independent of segmental chromosome aberrations (SCAs); only 1p loss decreased EFS (5-year EFS ± SD in patients 1p loss and no 1p loss, 62% ± 13% and 87% ± 3%, respectively; P = .019) but not OS (5-year OS ± SD, 92% ± 8% and 97% ± 2%, respectively). In patients ≥ 18 months, only SCAs led to relapse and death, with 11q loss as the strongest marker (11q loss and no 11q loss: 5-year EFS ± SD, 48% ± 16% and 85% ± 7%, P = .033; 5-year OS ± SD, 46% ± 22% and 92% ± 6%, P = .038).

CONCLUSION

Genomic aberrations of resectable non-MYCN-amplified stage 2 neuroblastomas have a distinct age-dependent prognostic impact. Chromosome 1p loss is a risk factor for relapse but not for diminished OS in patients < 18 months, SCAs (especially 11q loss) are risk factors for reduced EFS and OS in those > 18months. In older patients with SCA, a randomized trial of postoperative chemotherapy compared with observation alone may be indicated.

Tailoring Therapy for Children With Neuroblastoma on the Basis of Risk Group Classification: Past, Present, and Future

For children with neuroblastoma, the likelihood of cure varies widely according to age at diagnosis, disease stage, and tumor biology. Treatments are tailored for children with this clinically heterogeneous malignancy on the basis of a combination of markers that are predictive of risk of relapse and death. Sequential risk-based, cooperative-group clinical trials conducted during the past 4 decades have led to improved outcome for children with neuroblastoma. Increasingly accurate risk classification and refinements in treatment stratification strategies have been achieved with the more recent discovery of robust genomic and molecular biomarkers. In this review, we discuss the history of neuroblastoma risk classification in North America and Europe and highlight efforts by the International Neuroblastoma Risk Group (INRG) Task Force to develop a consensus approach for pretreatment stratification using seven risk criteria including an image-based staging system-the INRG Staging System. We also update readers on the current Children's Oncology Group risk classifier and outline plans for the development of a revised 2021 Children's Oncology Group classifier that will incorporate INRG Staging System criteria to facilitate harmonization of risk-based frontline treatment strategies conducted around the globe. In addition, we discuss new approaches to establish increasingly robust, future risk classification algorithms that will further refine treatment stratification using machine learning tools and expanded data from electronic health records and the INRG Data Commons.

Bioinformatic Identification of Neuroblastoma Microenvironment-Associated Biomarkers with Prognostic Value

The microenvironment plays a vital role in the tumor recurrence of neuroblastoma. This research aimed at exploring prognostic genes that are involved in neuroblastoma microenvironment. We used “estimate” R package to calculate the immune/stromal/ESTIMATE scores of each sample of ArrayExpress dataset E-MTAB-8248 based on the ESTIMATE algorithm. Then we found that immune/stromal/ESTIMATE scores were not correlated with age/chromosome 11q, but tumor stage, MYCN gene amplifications, and chromosome 1p. Samples were then divided into high- and low-score groups, and 280 common differentially expressed genes (DEGs) were identified. 64 potential prognostic genes were harvested through overall survival analysis from the common DEGs. 14 prognostic genes (ABCA6, SEPP1, SLAMF8, GPR171, ABCA9, ARHGAP15, IL7R, HLA-DPB1, GZMA, GPR183, CCL19, ITK, FGL2, and CD1C) were obtained after screening in two independent cohorts. GO and KEGG analysis discovered that common DEGs and 64 potential prognostic genes are mainly involved in T-cell activation, lymphocyte activation regulation, leukocyte migration, and the interaction of cytokines and cytokine receptors. Correlation analysis showed that all prognostic genes were negatively correlated with MYCN amplification. Cox analysis identified 5 independent prognostic genes (ARHGAP15, ABCA9, CCL19, SLAMF8, and CD1C).

Distribution of segmental chromosomal alterations in neuroblastoma

BACKGROUND

Neuroblastoma (NB) is a heterogeneous tumor with extremely diverse prognosis according to clinical and genetic factors such as specific combinations of chromosomal imbalances.

METHODS

Molecular karyotyping data from a national neuroblastic tumor database of 155 NB samples were analyzed and related to clinical data.

RESULTS

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.

CONCLUSIONS

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.

Development of differentiation modulators and targeted agents for treating neuroblastoma

Neuroblastoma (NB) is one of the most common pediatric malignancies. Easy metastasis, poor prognosis, and a high degree of heterogeneity of NB hinder its successful treatment. Several different therapeutic strategies have been developed to overcome these problems, including differentiation and targeted therapy. In this review, we summarize the recent development of differentiation modulators and targeted agents for treating NB. Several promising targets of NB were also discussed.

Somatic structural variation targets neurodevelopmental genes and identifies SHANK2 as a tumor suppressor in neuroblastoma

Neuroblastoma is a malignancy of the developing sympathetic nervous system that accounts for 12% of childhood cancer deaths. Like many childhood cancers, neuroblastoma shows a relative paucity of somatic single-nucleotide variants (SNVs) and small insertions and deletions (indels) compared to adult cancers. Here, we assessed the contribution of somatic structural variation (SV) in neuroblastoma using a combination of whole-genome sequencing (WGS) of tumor-normal pairs (n = 135) and single-nucleotide polymorphism (SNP) genotyping of primary tumors (n = 914). Our study design allowed for orthogonal validation and replication across platforms. SV frequency, type, and localization varied significantly among high-risk tumors. MYCN nonamplified high-risk tumors harbored an increased SV burden overall, including a significant excess of tandem duplication events across the genome. Genes disrupted by SV breakpoints were enriched in neuronal lineages and associated with phenotypes such as autism spectrum disorder (ASD). The postsynaptic adapter protein-coding gene, SHANK2, located on Chromosome 11q13, was disrupted by SVs in 14% of MYCN nonamplified high-risk tumors based on WGS and 10% in the SNP array cohort. Expression of SHANK2 was low across human-derived neuroblastoma cell lines and high-risk neuroblastoma tumors. Forced expression of SHANK2 in neuroblastoma cells resulted in significant growth inhibition (P = 2.6 × 10-2 to 3.4 × 10-5) and accelerated neuronal differentiation following treatment with all-trans retinoic acid (P = 3.1 × 10-13 to 2.4 × 10-30). These data further define the complex landscape of somatic structural variation in neuroblastoma and suggest that events leading to deregulation of neurodevelopmental processes, such as inactivation of SHANK2, are key mediators of tumorigenesis in this childhood cancer.

The prognostic strength of serum LDH and serum ferritin in children with neuroblastoma: A report from the International Neuroblastoma Risk Group (INRG) project

PURPOSE

Age, MYCN status, stage, and histology have been used as neuroblastoma (NB) risk factors for decades. Serum lactate dehydrogenase (LDH) and serum ferritin are reproducible, easily obtained, and prognostic, though never used in risk stratification, except one German trial. We analyzed the prognostic strength of LDH and ferritin, overall, within high-risk NB, and by era, using the International Neuroblastoma Risk Group Data Commons.

PATIENTS AND METHODS

Children with NB (1990-2016) were categorized into LDH (n = 8867) and ferritin (n = 8575) risk groups using EFS. Cox models compared the prognostic strength of LDH and ferritin to age, MYCN status, and INSS stage.

RESULTS

Higher LDH conferred worse EFS, overall (5-year EFS) (100-899 IU/L: 76 ± 0.6%; 0-99 or 900-1399 IU/L: 60 ± 1.2%; ≥1400 IU/L: 36 ± 1.2%; P < .0001), and in high-risk NB post-2009 (3-year EFS) (117-381 IU/L: 67 ± 8.9%; 382-1334 IU/L: 58 ± 4.4%; 0-116 or ≥1335 IU/L: 46 ± 3.9%; P = .003). Higher ferritin conferred worse EFS, overall (5-year EFS) (1-29 ng/mL: 87 ± 0.9%; 0 or 30-89 ng/mL: 74 ± 0.8%; ≥90 ng/mL: 48 ± 0.9%; P < .0001), and in high-risk NB post-2009 (3-year EFS) (1-53 ng/mL: 71 ± 9.3%; 0 or 54-354 ng/mL: 55 ± 4.7%; ≥355 ng/mL: 34 ± 6.1%; P = .0008). In multivariable analyses adjusting for age, MYCN, and stage, LDH and ferritin maintained independent prognostic ability (P < .0001; adjusted HRs (95% CI): 1.7 (1.5-1.9), 2.3 (2.0-2.7), respectively).

CONCLUSIONS

LDH and ferritin are strongly prognostic in NB, overall and within high-risk NB patients treated post-2009 with modern therapy. LDH and ferritin show promise for (a) identifying ultra-high-risk; (b) refining risk stratification; and (c) clinical utility in low-/middle-income countries. Routine collection of LDH and ferritin should be reinitiated for evolving NB risk stratification.

Neuroblastoma: An Updated Review on Biology and Treatment

BACKGROUND

Neuroblastoma (NB) is the second leading extracranial solid tumors of early childhood and clinically characterized by the presence of round, small, monomorphic cells with excess nuclear pigmentation (hyperchromasia).Owing to a lack of definitive treatment against NB and less survival rate in high-risk patients, there is an urgent requirement to understand molecular mechanisms associated with NB in a better way, which in turn can be utilized for developing drugs towards the treatment of NB in human.

OBJECTIVES

In this review, an approach was adopted to understand major risk factors, pathophysiology, the molecular mechanism associated with NB, and various therapeutic agents that can serve as drugs towards the treatment of NB in humans.

CONCLUSION

Numerous genetic (e.g., MYCN amplification), perinatal, and gestational factors are responsible for developing NB. However, no definite environmental or parental exposures responsible for causing NB have been confirmed to date. Though intensive multimodal treatment approaches, namely, chemotherapy, surgery & radiation, may help in improving the survival rate in children, these approaches have several side effects and do not work efficiently in high-risk patients. However, recent studies suggested that numerous phytochemicals, namely, vincristine, and matrine have a minimal side effect in the human body and may serve as a therapeutic drug during the treatment of NB. Most of these phytochemicals work in a dose-dependent manner and hence must be prescribed very cautiously. The information discussed in the present review will be useful in the drug discovery process as well as treatment and prevention on NB in humans.