MYCN gene amplification is a powerful prognostic factor even in infantile neuroblastoma detected by mass screening

MYCN Impact on High-Risk Neuroblastoma: From Diagnosis and Prognosis to Targeted Treatment

Simple Summary

Neuroblastoma is one of the most diffuse and the deadliest cancer in children. While many advances have been made in the last few decades to improve patients’ outcome, high-risk neuroblastoma (HR-NB) still shows a very aggressive pattern of development and poor prognosis, with only a 50% chance of 5-year survival. Moreover, while many factors contribute to defining the high-risk condition, MYCN status is well established as the major element in pathology disclosure. The aim of this review is to describe the current knowledge in the diagnosis, prognosis and therapeutic approaches of HR-NB, particularly in relation to MYCN. The review highlights how MYCN influences the HR-NB scenario and the new therapeutic approaches that are currently proposed to target it, in consideration of MYCN as a highly relevant target for HR-NB patient management.

Abstract

Among childhood cancers, neuroblastoma is the most diffuse solid tumor and the deadliest in children. While to date, the pathology has become progressively manageable with a significant increase in 5-year survival for its less aggressive form, high-risk neuroblastoma (HR-NB) remains a major issue with poor outcome and little survivability of patients. The staging system has also been improved to better fit patient needs and to administer therapies in a more focused manner in consideration of pathology features. New and improved therapies have been developed; nevertheless, low efficacy and high toxicity remain a staple feature of current high-risk neuroblastoma treatment. For this reason, more specific procedures are required, and new therapeutic targets are also needed for a precise medicine approach. In this scenario, MYCN is certainly one of the most interesting targets. Indeed, MYCN is one of the most relevant hallmarks of HR-NB, and many studies has been carried out in recent years to discover potent and specific inhibitors to block its activities and any related oncogenic function. N-Myc protein has been considered an undruggable target for a long time. Thus, many new indirect and direct approaches have been discovered and preclinically evaluated for the interaction with MYCN and its pathways; a few of the most promising approaches are nearing clinical application for the investigation in HR-NB.

Infantile mediastinal neuroblastoma presenting as an oncologic emergency: usefulness of serum-based MYCN gene amplification analysis for risk stratification

We reported two infantile cases of mediastinal neuroblastoma with life-threatening tracheal obstructions presenting as oncologic emergencies that were successfully treated per tentative risk classification using serum-based MYCN gene amplification (MNA) analysis. Tentative risk stratification based on age, tumour location and serum-based MNA status may be useful in patients with neuroblastoma presenting as oncologic emergencies who require urgent therapy stratification but for whom tumor-based molecular diagnoses cannot be established.

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.

[Clinical features of neuroblastoma: an analysis of 44 children]

OBJECTIVE

To study the clinical features of neuroblastoma (NB) and the factors influencing survival rate.

METHODS

A total of 44 children with NB who were admitted from April 2016 to February 2020 were enrolled as research subjects. A retrospective analysis was performed on their medical data and follow-up data.

RESULTS

The common clinical symptoms of these 44 children were fever (10/44, 23%), mass (9/44, 20%), abdominal pain (8/44, 18%), cough (7/44, 16%), pale complexion (3/44, 7%), claudication (2/44, 5%), and abnormal activity (2/44, 5%). According to the INSS stage, 2 children (4%) had stage I NB, 5 children (11%) had stage II NB, 5 children (11%) had stage III NB, and 32 children (73%) had stage IV NB. The mean follow-up time was (15.3±1.5) months, with a recurrence rate of 20% and an overall survival rate of 82%. Among the 44 children, 29 (66%) achieved event-free survival and 7 (16%) had survival with tumor. The univariate analysis showed that a pathological type of NB and an increase in serum neuron-specific enolase (NSE) decreased the overall survival rate of children with NB (P<0.05).

CONCLUSIONS

The clinical symptoms of children with NB are not specific at the first visit. Fever, abdominal pain, and mass are common symptoms, and there is a high proportion of children in the advanced stage. The pathological type of NB and an increase in serum NSE may be associated with a reduction in the overall survival rate of children with NB.

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).

Biochemical testing for neuroblastoma using plasma free 3-O-methyldopa, 3-methoxytyramine, and normetanephrine

BACKGROUND

Neuroblastoma, the most common extracranial solid tumor of childhood, produces catecholamines that are metabolized within tumor cells. Homovanillic acid (HVA) and vanillylmandelic acid (VMA), the end products of catecholamine metabolism, have limited accuracy for testing of the tumors. This study assessed whether metabolites produced in earlier steps of catecholamine metabolism might offer improved diagnostic accuracy over urinary HVA and VMA.

PROCEDURE

Plasma concentrations of 3-methoxytyramine, normetanephrine, and metanephrine were measured in two pediatric cohorts: (i) 96 children with confirmed neuroblastoma and (ii) 41 children with signs and symptoms of a catecholamine-producing tumor or other neoplasms and in whom neuroblastoma was excluded. Additional measurements of plasma 3-O-methyldopa and relationships of metabolites to MYCN amplification were examined in patient subgroups.

RESULTS

Overall, 94 of the 96 patients with neuroblastoma had concentrations of 3-methoxytyramine or normetanephrine above age-specific upper limits of reference intervals, providing a diagnostic sensitivity of 97.9% that was higher (P < 0.0001) than that of 82.2% for HVA and VMA. One of the two patients with normal plasma results showed an elevation of plasma 3-O-methyldopa. Diagnostic specificities were, respectively, 95.1% and 84.8%. Areas under receiver-operating characteristic curves confirmed the superior diagnostic power of the plasma than the urinary test (0.994 vs 0.945; P = 0.0095). Ratios of plasma 3-methoxytyramine to normetanephrine were 7.2-fold higher (P < 0.0001) for patients who had neuroblastomas with MYCN amplification than without MYCN amplification.

CONCLUSIONS

Measurements of plasma 3-methoxytyramine and normetanephrine provide a highly accurate diagnostic test for neuroblastoma and also offer potential for prognostic risk stratification.

Results of a prospective clinical trial JN-L-10 using image-defined risk factors to inform surgical decisions for children with low-risk neuroblastoma disease: A report from the Japan Children's Cancer Group Neuroblastoma Committee

BACKGROUND

The present study sought to reduce the incidence of treatment complications of low-risk neuroblastoma by using image-defined risk factors (IDRFs) to inform the timing of surgical resection.

PROCEDURES

Eligible patients included children (<18 years of age) with stage 1 or 2 disease, children (<365 days of age) with stage 3 disease, and infants with stage 4S disease. In IDRF-negative cases, treatment was completed with surgical resection alone. In IDRF-positive cases, the timing of surgery was determined based on the IDRFs after low-dose chemotherapy with 2-3 of the following four drugs: vincristine, cyclophosphamide, pirarubicin, and carboplatin. The outcome measures were overall survival, progression-free survival, and adverse events. This study was registered with the UMIN Clinical Trials Registry (number 000004355).

RESULTS

Of the 60 patients screened between 2010 and 2013, 58 eligible patients were enrolled; 32 were identified as IDRF negative at diagnosis while 26 were identified as IDRF positive and underwent induction chemotherapy. The 3-year overall and progression-free survival rates of the 58 patients were 100% and 82.8% (95% confidence interval: 70.3-90.3), respectively. Neutropenia was the most frequently reported grade 3 or 4 chemotherapy-related form of toxicity (41.7%). With regard to surgical complications, 2.5% of all patients developed pleural effusion and ascites as early complications, while only 2.5% developed renal atrophy as a long-term complication. No fatal toxicities were observed.

CONCLUSION

Using IDRFs to inform surgical decision making for the treatment of low-risk neuroblastoma improved prognosis and reduced the incidence of long-term complications.

Expression of carcinoma, apoptosis, and cell-death-related genes are determinants for sensitivity of pediatric cancer cell lines to lysis by natural killer cells

Natural killer (NK) cells have potential utility in pediatric cancer immunotherapy for their ability to lyse diverse tumor targets, lack of dependence on mutation-associated tumor antigens, and for their relative safety demonstrated so far in clinical trials. Here, we evaluate the cytotoxic potential of expanded NK cells against a well-characterized panel of pediatric cancer cell lines representing Ewing sarcoma, rhabdomyosarcoma, neuroblastoma, lymphoma, leukemia, and brain tumors. We correlate their sensitivity NK cell lysis with tumor phenotypic, transcriptomic, and genetic determinants, and correlate known immunogenetic determinants with donor NK cell potency. Although ligand expression on cell lines stratified according to hematologic versus nonhematologic cancer types, the sensitivity to NK cell lysis varied widely and did not correlate with cancer type, expression of individual activating or inhibitory ligands, gene-expression clusters of NK cell ligands, disease status (newly diagnosed or relapsed), or MYCN amplification. Rather, sensitivity to NK cell-mediated lysis was associated with a novel 96-gene cluster of predominantly carcinoma-, apoptosis-, and cell death-related pathways, and with functional p53 status. NK cell potency was strongly associated with activating KIR gene content, but not with KIR/KIR-ligand mismatch. This study suggests that adoptive immunotherapy with expanded NK cells has the potential for a wide range of pediatric cancers, identifies potential biomarkers of efficacy and response, and establishes a foundation for using this cell line panel for the preclinical evaluation of immunotherapies.

Opportunities and challenges of circulating biomarkers in neuroblastoma

Molecular analysis of nucleic acid and protein biomarkers is becoming increasingly common in paediatric oncology for diagnosis, risk stratification and molecularly targeted therapeutics. However, many current and emerging biomarkers are based on analysis of tumour tissue, which is obtained through invasive surgical procedures and in some cases may not be accessible. Over the past decade, there has been growing interest in the utility of circulating biomarkers such as cell-free nucleic acids, circulating tumour cells and extracellular vesicles as a so-called liquid biopsy of cancer. Here, we review the potential of emerging circulating biomarkers in the management of neuroblastoma and highlight challenges to their implementation in the clinic.

A prospective evaluation of liquid biopsy for detecting MYCN amplification in neuroblastoma patients

Background

Our previous study reported a method for determining MYCN gene amplification (MNA) status using cell-free DNA in serum. We prospectively analyzed the serum MNA status using sera obtained before the initial diagnosis from patients with neuroblastoma and evaluated the utility of this method.

Methods

Eighty patients were enrolled in the study. The serum MYCN/NAGK ratio was assessed for all cases.

Results

Fifteen cases showed serum MNA, while 65 did not. Of the 80 total patients, tumor samples for a genetic analysis were not obtained from 27 due to the patients’ condition or other reasons. For the 43 of 80 cases that had both serum and tumor samples analyzed, the serum-based MNA status matched to tumor-based MNA status (P < 0.001). The sensitivity and the specificity were 100%, respectively. Seven of 15 cases who diagnosed as MNA by serum-based MNA status were <18 months of age, and tumor samples were not obtained from 4 of these cases. Based on the serum MNA status, these cases were able to start treatment immediately. The 4-year event-free survival rates of cases with and without MNA in sera were 37.5% and 84.8%, respectively (P < 0.001).

Conclusion

The serum-based MNA status was useful for precisely predicting the MNA status in tumor and it has clinical benefits for predicting risk stratification in patients for whom obtaining tumor samples is difficult.

Inhibition of N-myc expression sensitizes human neuroblastoma IMR-32 cells expressing caspase-8 to TRAIL

Objectives

This study aims to explore the roles of N‐myc and caspase‐8 in TRAIL‐resistant IMR‐32 cells which exhibit MYCN oncogene amplification and lack caspase‐8 expression.

Materials and methods

We established N‐myc–downregulated IMR‐32 cells using shRNA lentiviral particles targeting N‐myc and examined the effect the N‐myc inhibition on TRAIL susceptibility in human neuroblastoma IMR‐32 cells expressing caspase‐8.

Results

Cisplatin treatment in IMR‐32 cells increased the expression of death receptor 5 (DR5; TRAIL‐R2), but not other receptors, via downregulation of NF‐κB activity. However, the cisplatin‐mediated increase in DR5 failed to induce cell death following TRAIL treatment. Furthermore, interferon (IFN)‐γ pretreatment increased caspase‐8 expression in IMR‐32 cells, but cisplatin failed to trigger TRAIL cytotoxicity. We downregulated N‐myc expression in IMR‐32 cells using N‐myc–targeting shRNA. These cells showed decreased growth rate and Bcl‐2 expression accompanied by a mild collapse in the mitochondrial membrane potential as compared with those treated with scrambled shRNA. TRAIL treatment in N‐myc–negative cells expressing caspase‐8 following IFN‐γ treatment significantly triggered apoptotic cell death. Concurrent treatment with cisplatin enhanced TRAIL‐mediated cytotoxicity, which was abrogated by an additional pretreatment with DR5:Fc chimera protein.

Conclusions

N‐myc and caspase‐8 expressions are involved in TRAIL susceptibility in IMR‐32 cells, and the combination of treatment with cisplatin and TRAIL may serve as a promising strategy for the development of therapeutics against neuroblastoma that is controlled by N‐myc and caspase‐8 expression.

Accumulation of potential driver genes with genomic alterations predicts survival of high-risk neuroblastoma patients

Background

Neuroblastoma is the most common pediatric malignancy with heterogeneous clinical behaviors, ranging from spontaneous regression to aggressive progression. Many studies have identified aberrations related to the pathogenesis and prognosis, broadly classifying neuroblastoma patients into high- and low-risk groups, but predicting tumor progression and clinical management of high-risk patients remains a big challenge.

Results

We integrate gene-level expression, array-based comparative genomic hybridization and functional gene-interaction network of 145 neuroblastoma patients to detect potential driver genes. The drivers are summarized into a driver-gene score (DGscore) for each patient, and we then validate its clinical relevance in terms of association with patient survival. Focusing on a subset of 48 clinically defined high-risk patients, we identify 193 recurrent regions of copy number alterations (CNAs), resulting in 274 altered genes whose copy-number gain or loss have parallel impact on the gene expression. Using a network enrichment analysis, we detect four common driver genes, ERCC6, HECTD2, KIAA1279, EMX2, and 66 patient-specific driver genes. Patients with high DGscore, thus carrying more copy-number-altered genes with correspondingly up- or down-regulated expression and functional implications, have worse survival than those with low DGscore (P = 0.006). Furthermore, Cox proportional-hazards regression analysis shows that, adjusted for age, tumor stage and MYCN amplification, DGscore is the only significant prognostic factor for high-risk neuroblastoma patients (P = 0.008).

Conclusions

Integration of genomic copy number alteration, expression and functional interaction-network data reveals clinically relevant and prognostic putative driver genes in high-risk neuroblastoma patients. The identified putative drivers are potential drug targets for individualized therapy.

Reviewers

This article was reviewed by Armand Valsesia, Susmita Datta and Aleksandra Gruca.

Electronic supplementary material

The online version of this article (10.1186/s13062-018-0218-5) contains supplementary material, which is available to authorized users.

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.

Identification of the genetic and clinical characteristics of neuroblastomas using genome-wide analysis

To provide better insight into the genetic signatures of neuroblastomas, we analyzed 500 neuroblastomas (included specimens from JNBSG) using targeted-deep sequencing for 10 neuroblastoma-related genes and SNP arrays analysis. ALK expression was evaluated using immunohistochemical analysis in 259 samples. Based on genetic alterations, the following 6 subgroups were identified: groups A (ALK abnormalities), B (other gene mutations), C (MYCN amplification), D (11q loss of heterozygosity [LOH]), E (at least 1 copy number variants), and F (no genetic changes). Groups A to D showed advanced disease and poor prognosis, whereas groups E and F showed excellent prognosis. Intriguingly, in group A, MYCN amplification was not a significant prognostic marker, while high ALK expression was a relevant indicator for prognosis (P = 0.033). Notably, the co-existence of MYCN amplification and 1p LOH, and the co-deletion of 3p and 11q were significant predictors of relapse (P = 0.043 and P = 0.040). Additionally, 6q/8p LOH and 17q gain were promising indicators of survival in patients older than 5 years, and 1p, 4p, and 11q LOH potentially contributed to outcome prediction in the intermediate-risk group. Our genetic overview clarifies the clinical impact of genetic signatures and aids in the better understanding of genetic basis of neuroblastoma.

MYCN amplification predicts poor prognosis based on interphase fluorescence in situ hybridization analysis of bone marrow cells in bone marrow metastases of neuroblastoma

BACKGROUND

MYCN gene amplification is related to risk stratification. Therefore it is important to identify accurately the level of the MYCN gene as early as possible in neuroblastoma (NB); however, for patients with bone marrow (BM) metastasis who need chemotherapy before surgery, timely detection of the MYCN gene is not possible due to the unavailability of primary tumors.

METHODS

MYCN gene status was evaluated in 81 BM metastases of NB by interphase fluorescence in situ hybridization (FISH) analysis of BM cells. The clinicobiological characteristics and prognostic impact of MYCN amplification in NB metastatic to BM were analyzed.

RESULTS

MYCN amplification was found in 16% of patients with metastases, and the results were consistent with the primary tumors detected by pathological tissue FISH. MYCN amplification was associated with age, lactate dehydrogenase (LDH) levels and prognosis (P = 0.038, P < 0.001, P = 0.026). Clinical outcome was poorer in patients with MYCN amplification than in those without amplification (3-year EFS 28.8 ± 13.1 vs. 69.7 ± 5.7%, P = 0.005; 3-year OS 41.5 ± 14.7 vs. 76.7 ± 5.5%, P = 0.005).

CONCLUSIONS

MYCN amplification predicts a poor outcome in NB metastatic to BM, and interphase FISH of bone marrow cells provides a timely direct and valid method to evaluate the MYCN gene status.

The novel thiosemicarbazone, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), inhibits neuroblastoma growth in vitro and in vivo via multiple mechanisms

Background

Neuroblastoma is a relatively common and highly belligerent childhood tumor with poor prognosis by current therapeutic approaches. A novel anti-cancer agent of the di-2-pyridylketone thiosemicarbazone series, namely di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), demonstrates promising anti-tumor activity. Recently, a second-generation analogue, namely di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), has entered multi-center clinical trials for the treatment of advanced and resistant tumors. The current aim was to examine if these novel agents were effective against aggressive neuroblastoma in vitro and in vivo and to assess their mechanism of action.

Methods

Neuroblastoma cancer cells as well as immortalized normal cells were used to assess the efficacy and selectivity of DpC in vitro. An orthotopic SK-N-LP/Luciferase xenograft model was used in nude mice to assess the efficacy of DpC in vivo. Apoptosis in tumors was confirmed by Annexin V/PI flow cytometry and H&E staining.

Results

DpC demonstrated more potent cytotoxicity than Dp44mT against neuroblastoma cells in a dose- and time-dependent manner. DpC significantly increased levels of phosphorylated JNK, neuroglobin, cytoglobin, and cleaved caspase 3 and 9, while decreasing IkBα levels in vitro. The contribution of JNK, NF-ĸB, and caspase signaling/activity to the anti-tumor activity of DpC was verified by selective inhibitors of these pathways. After 3 weeks of treatment, tumor growth in mice was significantly (p < 0.05) reduced by DpC (4 mg/kg/day) given intravenously and the agent was well tolerated. Xenograft tissues showed significantly higher expression of neuroglobin, cytoglobin, caspase 3, and tumor necrosis factor-α (TNFα) levels and a slight decrease in interleukin-10 (IL-10).

Conclusions

DpC was found to be highly potent against neuroblastoma, demonstrating its potential as a novel therapeutic for this disease. The ability of DpC to increase TNFα in tumors could also promote the endogenous immune response to mediate enhanced cancer cell apoptosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0330-x) contains supplementary material, which is available to authorized users.

Serum-Based Quantification of MYCN Gene Amplification in Young Patients with Neuroblastoma: Potential Utility as a Surrogate Biomarker for Neuroblastoma

We previously developed a method for determining MYCN gene amplification status using cell-free DNA fragments released from cancer cells into the blood of patients with neuroblastoma (NB). Here, we analyzed the relationship between MYCN amplification (MNA) status and neuroblastoma prognosis. We screened serum samples from 151 patients with NB for MNA, using real-time quantitative PCR, and compared the results with MYCN status determined using paired tumor samples. We additionally investigated whether MNA status correlates with patient survival. When a cut-off value of 5 was used, serum-based MNA analysis was found to show good sensitivity (86%) and very high specificity (95%). The sensitivities for stage 1 and 2 might be acceptable, even though it is not as good as for stage 3 and 4 (67% for stage 1 and 2, 92% for stage 3, and 87% for stage 4). MNA status correlated with overall survival in our cohort of 82 patients, with survival data available (p < 0.01). The hazard ratio of MNA status was 4.98 in patients diagnosed at less than 18 months of age (95% confidence interval, 1.00–24.78), and 1.41 (95% confidence interval, 0.63–3.14) for those diagnosed at 18 months of age or older. Serum-based MNA analysis is rapid and non-invasive compared with tumor-based MNA analysis, and has potential to predict tumor MNA status. There is still a room to improve the sensitivity of the test for tumors of stages 1 and 2, nonetheless this assay might help to determine therapeutic strategies prior to tumor biopsy, especially for patients with a life-threatening condition, as well as for patients of less than 18 months of age whose risk-grouping and treatment allocation depends on their MNA status.

High incidence of MYCN amplification in a Moroccan series of neuroblastic tumors: comparison to current biological data

MYCN protooncogene status was assessed for the first time in Morocco in peripheral neuroblastic tumors, including neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. Correlations with age at diagnosis, stage, mitosis-karyorrhexis index, differentiation, and Shimada histology were evaluated. Thirty-six formalin-fixed, paraffin-embedded peripheral neuroblastic tumor tissue specimens collected between 2007 and 2010 from the Pathology Department were assessed for MYCN amplification using fluorescence in situ hybridization. MYCN amplification was found in 27.8% of cases. An association of MYCN amplification with unfavorable Shimada grading, higher mitosis-karyorrhexis index, and undifferentiated morphologic phenotype was found. We found no correlation with older age, advanced stage, or the presence of metastasis. Our results suggested that the presence of MYCN amplification is a strong biological indicator of a poor outcome and aggressive disease in neuroblastoma and nodular ganglioneuroblastoma.

Surgical treatment of neuroblastoma: twenty-three years of experience at a single institution

PURPOSE

Neuroblastoma (NB) is treated with surgery, chemotherapy and radiotherapy. We assessed the effects of surgical resection on the outcome over a 23-year period at our institution.

METHODS

85 children were included with a median age at diagnosis of 2.0 (range 0.1-15) years. We assessed the correlation of the complete surgical resection (CR) rate, metastases, NMYC amplification (NMYCA) and chemotherapeutic response with the 5-year overall survival (OS).

RESULTS

The INSS stage of NB was 1 in 11 (13 %) patients, 2 in 10 (11 %), 3 in 13 (17 %), 4 in 46 (53 %) and 4S in five patients (6 %). Fifty-two (61 %) patients had high-risk NB and 22 (26 %) had NMYCA. The resection was complete in 72 (85 %) patients, incomplete (ICR) in seven (8 %) and six (7 %) patients did not undergo surgery. Fifty-five patients were administered neoadjuvant and 61 were administered adjuvant chemotherapy (high-dose, n = 50). The OS (5 year) was 68 %: stage 1 (100 %), 2 (90 %), 3 (77 %), 4 (52 %), 4S (80 %) and high-risk NB (52 %). The OS in high-risk NB patients was correlated with a good chemotherapeutic response of the primary tumour, with a RR for mortality = 0.3 (95 % CI 0.1-0.7; p = 0.01), but not with the CR, which had an RR = 0.9 (95 % CI 0.3-2.4; p = 0.84).

CONCLUSIONS

The OS in high-risk NB patients was related to a good histological chemotherapeutic response, but not with complete excision of the primary tumour.

Ten challenges in the management of neuroblastoma

Neuroblastoma is a complex disease with many contradictions and challenges. It is, by and large, a cancer of babies and preschool children, but it does occur, albeit increasingly rarely, in older children, adolescents and young adults. The prognosis is very variable, with outcome related to age, stage and molecular pathology. Neuroblastoma may behave in an almost benign way, with spontaneous regression in some infants, but the majority of older patients have high-risk disease, which is usually fatal, despite best current treatments. As a rare disease, international collaboration is essential to run clinical trials of adequate statistical power to answer important questions in a reasonable time frame. High-risk disease requires multimodality therapy including chemotherapy, surgery and radiotherapy as well as biological and immunological treatments for optimal outcomes. Innovative treatment approaches, sometimes associated with appreciable toxicity, offer hope for the future but, despite parental wishes, cannot be generally implemented without adequate assessment in clinical trials.

Krüppel-like factor 4 (KLF4) suppresses neuroblastoma cell growth and determines non-tumorigenic lineage differentiation

Neuroblastoma (NB) is an embryonal tumor and possesses a unique propensity to exhibit either a spontaneous regression or an unrestrained growth. However, the underlying mechanism for this paradoxical clinical outcome remains largely unclear. Quantitative RT-PCR analysis on 102 primary NB tumors revealed that lower Krüppel-like factor 4 (KLF4) expression is frequently found in the unfavorable NB (Mann-Whitney test, P=0.027). In particular with the high-risk factors such as age of patient >1 year, MYCN amplification and low TRKA expression, the decreased expression of KLF4 was significantly associated with an unfavorable NB outcome. Despite knockdown of KLF4 alone is not sufficient to increase tumorigenicity of NB cells in vivo, stable expression of KLF4 short hairpin RNA in Be(2)-C cells significantly promoted growth of NB cells and inhibited cell differentiation toward fibromuscular lineage. In concordant with these observations, overexpression of KLF4 in SH-SY-5Y cells profoundly suppressed cell proliferation by direct upregulation of cell-cycle inhibitor protein p21(WAF1/CIP1), and knocking down p21(WAF1/CIP1) could partially rescue the suppressive effect of KLF4. Importantly, KLF4 overexpressing cells have lost their neuroblastic phenotypes, they were epithelial-like, strongly substrate-adherent, expressing smooth muscle marker and became non-tumorigenic, suggesting that KLF4 expression is crucial for lineage determination of NB cells, probably, favoring spontaneous tumor regression. Subsequent global gene expression profiling further revealed that transforming growth factor beta (TGFβ) and cell-cycle pathways are highly dysregulated upon KLF4 overexpression, and myogenic modulators, MEF2A and MYOD1 were found significantly upregulated. Taken together, we have demonstrated that KLF4 contributes to the favorable disease outcome by directly mediating the growth and lineage determination of NB cells.

Reevaluation of trkA expression as a biological marker of neuroblastoma by high-sensitivity expression analysis--a study of 106 primary neuroblastomas treated in a single institute

BACKGROUND/PURPOSE

It has previously been shown that neuroblastomas with favorable prognosis often express a high level of nerve growth factor receptor trkA. We performed an expression analysis of trkA in 106 NB samples based on the quantitative real-time polymerase chain reaction (PCR) and reevaluated the prognostic power of trkA.

MATERIALS AND METHODS

A total of 106 primary tumors from NB patients treated from 1988 to 2009 were analyzed. MYCN was amplified in 13 cases. TaqMan probe method was used for quantitative PCR. Primers and probes were designed to detect trkA I and trkA II, but not the oncogenic splice variant trkA III.

RESULTS

Expression analysis by real-time PCR revealed a wide range of expression levels of trkA within neuroblastoma tissues. Extremely low levels of trkA that were undetectable by semiquantitative PCR were able to be quantified by this method. trkA was predominantly expressed in tumors with favorable outcome. Further analysis of trkA expression was performed in a cohort excluding mass-screened neuroblastomas. Strikingly, multivariate analysis containing age, MYCN status, and trkA expression identified trkA as the only variable that independently predicts the prognosis of the 44 patients who presented clinically.

CONCLUSION

High-resolution expression analysis targeting trkA and trkA II may add more statistical power on trkA as a biological marker.

CD133 suppresses neuroblastoma cell differentiation via signal pathway modification

CD133 (prominin-1) is a transmembrane glycoprotein expressed on the surface of normal and cancer stem cells (tumor-initiating cells), progenitor cells, rod photoreceptor cells and a variety of epithelial cells. Although CD133 is widely used as a marker of various somatic and putative cancer stem cells, its contribution to the fundamental properties of cancer cells, such as tumorigenesis and differentiation, remains to be elucidated. In the present report, we found that CD133 was expressed in several neuroblastoma (NB) cell lines/tumor samples. Intriguingly, CD133 repressed NB cell differentiation, for example neurite extension and the expression of differentiation marker proteins, and was decreased by several differentiation stimuli, but accelerated cell proliferation, anchorage-independent colony formation and in vivo tumor formation of NB cells. NB cell line and primary tumor-sphere experiments indicated that the molecular mechanism of CD133-related differentiation suppression in NB was in part dependent on neurotrophic receptor RET tyrosine kinase regulation. RET transcription was suppressed by CD133 in NB cells and glial cell line-derived neurotrophic factor treatment failed to induce RET in CD133-expressing cells; RET overexpression rescued CD133-related inhibition of neurite elongation. Of note, CD133-related NB cell differentiation and RET repression were mainly dependent on p38MAPK and PI3K/Akt pathways. Furthermore, CD133 has a function in growth and RET expression in NB cell line- and primary tumor cell-derived tumor spheres. To the best of our knowledge, this is the first report of the function of CD133 in cancer cells and our findings may be applied to improve differentiation induction therapy for NB patients.

Systems biology and modeling in neuroblastoma: practicalities and perspectives

Neuroblastoma (NB) is a common pediatric malignancy characterized by clinical and biological heterogeneity. A host of prognostic markers are available, contributing to accurate risk stratification and appropriate treatment allocation. Unfortunately, outcome is still poor for many patients, indicating the need for a new approach with enhanced utilization of the available biological data. Systems biology is a holistic approach in which all components of a biological system carry equal importance. Systems biology uses mathematical modeling and simulation to investigate dynamic interactions between system components, as a means of explaining overall system behavior. Systems biology can benefit the biomedical sciences by providing a more complete understanding of human disease, enhancing the development of targeted therapeutics. Systems biology is largely contiguous with current approaches in NB, which already employ an integrative and pseudo-holistic approach to disease management. Systems modeling of NB offers an optimal method for continuing progression in this field, and conferring additional benefit to current risk stratification and management. Likewise, NB provides an opportunity for systems biology to prove its utility in the context of human disease, since the biology of NB is comprehensively characterized and, therefore, suited to modeling. The purpose of this review is to outline the benefits, challenges and fundamental workings of systems modeling in human disease, using a specific example of bottom-up modeling in NB. The intention is to demonstrate practical requirements to begin bridging the gap between biological research and applied mathematical approaches for the mutual gain of both fields, and with additional benefits for clinical management.

Risks and benefits of ending of mass screening for neuroblastoma at 6 months of age in Japan

PURPOSE

The mass screening (MS) for neuroblastoma (NB) at 6 months of age in Japan was discontinued in 2004. This study assessed the risks and benefits of MS based on an analysis of NB detected before or after discontinuation of MS in Japan.

METHODS

The clinical features and Brodeur's genetic type based on MYCN, DNA ploidy, and other genetic aberrations were assessed in 113 NB patients (20 cases after and 93 cases [55 MS cases] before the discontinuation of MS) older than 6 months treated at one institution since 1985.

RESULTS

The 20 patients with NBs detected after MS was discontinued ranged in age from 7 to 67 months, 12 patients were stage 4, and 11 patients would have been detected at 6 months of age if they had undergone MS. The Brodeur's genetic type of these 20 patients showed that 30% (6/20) were type 1 (low risk), 55% (11/20) were type 2A (intermediate risk), and 15% (3/20) were type 2B (high risk). Of 93 patients with NB detected before MS was discontinued, 60% (56/93) were type 1, 18% (17/93) were type 2A, and 22% (20/93) were type 2B. Among the type 2A patients, 82% (9/11) of the patients detected after MS was discontinued showed stage 4, whereas only 50% (9/18) of those diagnosed before MS was discontinued were stage 4. The genetic analysis using single nucleotide polymorphism (SNP) array for type 2A showed that the pattern of genetic aberration was equivalent in those detected either before or after MS was discontinued.

CONCLUSIONS

There was a decrease of type 1 and an increase of type 2A NB in patients after MS was discontinued in Japan. These results suggest that most of the type 1 detected by MS has regressed, and most of the type 2A detected by MS has appeared sporadically as advanced NB in patients older than 1 year.

Novel risk stratification of patients with neuroblastoma by genomic signature, which is independent of molecular signature

Human neuroblastoma remains enigmatic because it often shows spontaneous regression and aggressive growth. The prognosis of advanced stage of sporadic neuroblastomas is still poor. Here, we investigated whether genomic and molecular signatures could categorize new therapeutic risk groups in primary neuroblastomas. We conducted microarray-based comparative genomic hybridization (array-CGH) with a DNA chip carrying 2464 BAC clones to examine genomic aberrations of 236 neuroblastomas and used in-house cDNA microarrays for gene-expression profiling. Array-CGH demonstrated three major genomic groups of chromosomal aberrations: silent (GGS), partial gains and/or losses (GGP) and whole gains and/or losses (GGW), which well corresponded with the patterns of chromosome 17 abnormalities. They were further classified into subgroups with different outcomes. In 112 sporadic neuroblastomas, MYCN amplification was frequent in GGS (22%) and GGP (53%) and caused serious outcomes in patients. Sporadic tumors with a single copy of MYCN showed the 5-year cumulative survival rates of 89% in GGS, 53% in GGP and 85% in GGW. Molecular signatures also segregated patients into the favorable and unfavorable prognosis groups (P=0.001). Both univariate and multivariate analyses revealed that genomic and molecular signatures were mutually independent, powerful prognostic indicators. Thus, combined genomic and molecular signatures may categorize novel risk groups and confer new clues for allowing tailored or even individualized medicine to patients with neuroblastoma.