Changes In Neuroblastoma Research Articles

Landscape of Bone Marrow Metastasis in Human Neuroblastoma Unraveled by Transcriptomics and Deep Multiplex Imaging.

Simple SummaryBone marrow metastasis frequently occurs in patients with solid cancers and most often leads to poor outcome. Yet, the composition of bone marrow metastases, including tumor and surrounding cells, has so far not been characterized. Herein, we aimed to investigate the diversity of tumor and surrounding cells, i.e., the microenvironment, in bone marrow metastases, using the childhood tumor neuroblastoma as a model. To this end, we screened genome-wide datasets to define a panel of cell-specific markers for multiplex microscopy of metastatic bone marrow samples, and developed DeepFLEX, a computational pipeline for subsequent image analysis. Thereby, we identified 35,000 single cells covering metastasized tumor cells, and various types of developing immune and bone marrow cells. In parallel, we analyzed the transcriptome, i.e., all genes that are expressed as mRNA, of 38 patients with and without bone marrow metastasis. We found vast tumor cell diversity and identified a marker protein, FAIM2, which can help to identify a broader range of tumor cell variants. In addition we showed that tumor cell metastasis in the bone marrow is associated with an immune response resembling inflammation, and the presence of cells that can repress an immune attack against cancer cells. Our study suggests that metastatic tumor cells are shaping the bone marrow microenvironment and builds the basis to further investigate its clinical relevance.While the bone marrow attracts tumor cells in many solid cancers leading to poor outcome in affected patients, comprehensive analyses of bone marrow metastases have not been performed on a single-cell level. We here set out to capture tumor heterogeneity and unravel microenvironmental changes in neuroblastoma, a solid cancer with bone marrow involvement. To this end, we employed a multi-omics data mining approach to define a multiplex imaging panel and developed DeepFLEX, a pipeline for subsequent multiplex image analysis, whereby we constructed a single-cell atlas of over 35,000 disseminated tumor cells (DTCs) and cells of their microenvironment in the metastatic bone marrow niche. Further, we independently profiled the transcriptome of a cohort of 38 patients with and without bone marrow metastasis. Our results revealed vast diversity among DTCs and suggest that FAIM2 can act as a complementary marker to capture DTC heterogeneity. Importantly, we demonstrate that malignant bone marrow infiltration is associated with an inflammatory response and at the same time the presence of immuno-suppressive cell types, most prominently an immature neutrophil/granulocytic myeloid-derived suppressor-like cell type. The presented findings indicate that metastatic tumor cells shape the bone marrow microenvironment, warranting deeper investigations of spatio-temporal dynamics at the single-cell level and their clinical relevance.

Role of aryl hydrocarbon receptor in central nervous system tumors: Biological and therapeutic implications.

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, whose canonical pathway mainly regulates the genes involved in xenobiotic metabolism. However, it can also regulate several responses in a non-canonical manner, such as proliferation, differentiation, cell death and cell adhesion. AhR plays an important role in central nervous system tumors, as it can regulate several cellular responses via different pathways. The polymorphisms of the AHR gene have been associated with the development of gliomas. In addition, the metabolism of tumor cells promotes tumor growth, particularly in tryptophan synthesis, where some metabolites, such as kynurenine, can activate the AhR pathway, triggering cell proliferation in astrocytomas, medulloblastomas and glioblastomas. Furthermore, as part of the changes in neuroblastomas, AHR is able to downregulate the expression of proto-oncogene c-Myc, induce differentiation in tumor cells, and cause cell cycle arrest and apoptosis. Collectively, these data suggested that the modulation of the AhR pathway may downregulate tumor growth, providing a novel strategy for applications for the treatment of certain tumors through the control of the AhR pathway.

Abstract A01: Evaluation of hypoxia adaptation in neuroblastoma identifies reproducible transcriptional and phenotypic responses

Abstract Although metabolic adaptation is a cornerstone of the hypoxia response, very little is known about hypoxia-induced metabolic changes in neuroblastoma or how the metabolome influences phenotype. Identifying genes that regulate neuroblastoma metabolism and also influence clinical behavior may provide clues for novel therapeutic targets. Mixed linear models were used to identify differentially expressed genes between neuroblastoma cells grown in hypoxia or normoxia in two independent experiments (GEO accessions GSE17714 and GSE55391). Linear models were also used in to identify differentially expressed genes from tumors of two independent cohorts of neuroblastoma patients (GEO accession GSE16254 and EMBL accession E-MTAB-179) who survived compared to those that did not. We utilized a false discovery rate of 0.01 and fold change in the top or bottom 10% of all genes as a significance cutoff. qPCR was used to validate expression differences in multiple neuroblastoma cell lines. 157 genes, significantly exceeding chance (p < 1x10-6) on permutation testing, were present in both neuroblastoma cell line data sets, all but five of which showed consistent directionality of expression change from normoxia to hypoxia, including 44 involved in metabolism. These genes were enriched for hypoxia and metabolic pathways: HIF-1α transcription factor network (p = 1.3x10-11), glycolysis (p = 1.9x10-8) and fructose metabolism (p = 1.0x10-3). 826 genes, significantly exceeding chance (p < 1x10-6) were differentially expressed in both patient cohorts of 478 and 88 patients. These genes were enriched for cell cycle pathways (p = 4.5x10-7). Of these genes, nine of them were also differentially expressed in hypoxia compared to normoxia with consistent directionality, again more than expected by chance (p < 1x10-6). High expression in eight of the nine genes was also significantly associated with poor outcome in a Kaplan-Meier analysis of both of the patient cohorts evaluated. Three of these genes are part of the glycolytic pathway and three more are directly involved in cellular metabolism. In the SK-N-BE2 cell line, all eight of our identified genes are up-regulated in hypoxia (p < 0.05). Analysis of the LAN-5, La1-55n, SK-N-DZ cell lines and show similar results. MTT assays of proliferation show the expected decreased proliferation for all of these cell lines in 48 hours of hypoxia compared to normoxia (p < 0.05). Analysis of cell cycle by flow cytometry in SK-N-BE2 cells shows an increase of cells in G0/G1 in normoxia compared to hypoxia (58.3% vs. 71.5% p = 0.04) and decrease of cells in S phase (24.5% vs. 13.6%, p = 0.001). We have identified eight genes with increased expression in hypoxia and are associated with poor survival in patients. Efforts to use shRNA to alter cellular phenotype are ongoing. Citation Format: Mark A. Aplebaum, Aashish Jha, Alexandre Chlenski, Christopher Mariani, Clara Kao, Mildred Nelson, Kyle Hernandez, Helen Salwen, Marija Dobratic, Kevin White, Barbara Stranger, Susan L. Cohn. Evaluation of hypoxia adaptation in neuroblastoma identifies reproducible transcriptional and phenotypic responses. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr A01.

DNA methylation fingerprint of neuroblastoma reveals new biological and clinical insights.

To define the DNA methylation landscape of neuroblastoma and its clinicopathological impact. Microarray DNA methylation data were analyzed and associated with functional/regulatory genome annotation data, transcriptional profiles and clinicobiological parameters. DNA methylation changes in neuroblastoma affect not only promoters but also intragenic and intergenic regions at cytosine-phosphate-guanine (CpG) and non-CpG sites, and target functional chromatin domains of development and cancer-related genes such as CCND1. Tumors with diverse clinical risk showed differences affecting CpG and, remarkably, non-CpG sites. Non-CpG methylation observed essentially in clinically favorable cases was associated with the differentiation status of neuroblastoma and expression of key genes such as ALK. This epigenetic fingerprint of neuroblastoma provides new insights into the pathogenesis and clinical behavior of this pediatric tumor.

The Role of p14ARF Methylation in Neuroblastoma Minimal Residual Disease

Objectives: The aim of the present study is to investigate the clinical significance of epigenetic changes in neuroblastoma, we evaluated the relationship between therapeutic variables and the pattern of gene methylation in neuroblastoma cell lines. Methods: In this minimal residual disease model, cytotoxic effects of blocked p14ARF by a demethylating agent on KELLY and SHSY-5Y human neuroblastoma cell lines were assessed following addition of the drugs used in the Turkish Pediatric Oncology Group (TPOG) chemotherapy protocol. Drug induced effects on cell viability, cell damage and apoptotic cell death ratio were assessed with trypan blue dying. Cytotoxic effects differed among the used neuroblastoma cell lines. For the investigation of mechanisms of this effect, p14 ARF gen methylation and expression levels, and MYCN expression levels were targeted. Expressions of mRNA and protein were determined with real-time PCR and ELISA, respectively. Results: The p14 ARF gene expression levels in KELLY 5-aza-CdR, Vincristin, Vincristin+5aza-CdR, Dacarbazine, Ifosfamide+5-aza-CdR, Doxorubicine+5-aza-CdR, Etoposide+5aza-CdR groups were found to be significantly higher than those measured in corresponding groups of SHSY-5Y (p<0.05). The percentages of p14ARF gene promoter unmethylation were higher in MYCN (-) groups than MYCN (+) groups (p=0.034). Conclusion: In this pioneering study we suggest not only a new therapeutic approach for early or late relapses following the standard treatment protocols, but also demonstrate the effect of chemoterapeutic agents on p14 ARF gene. The present study suggests that clinically aggressive neuroblastoma cell lines have aberrant methylation of p14ARF genes and provides a

Identification of a novel recurrent 1q42.2‐1qter deletion in high risk MYCN single copy 11q deleted neuroblastomas

Neuroblastoma is an aggressive embryonal tumor that accounts for ∼15% of childhood cancer deaths. Hitherto, despite the availability of comprehensive genomic data on DNA copy number changes in neuroblastoma, relatively little is known about the genes driving neuroblastoma tumorigenesis. In this study, high resolution array comparative genome hybridization (CGH) was performed on 188 primary neuroblastoma tumors and 33 neuroblastoma cell lines to search for previously undetected recurrent DNA copy number gains and losses. A new recurrent distal chromosome 1q deletion (del(1)(q42.2qter)) was detected in seven cases. Further analysis of available array CGH datasets revealed 13 additional similar distal 1q deletions. The majority of all detected 1q deletions was found in high risk 11q deleted tumors without MYCN amplification (Fisher exact test p = 5.61 × 10(-5) ). Using ultra-high resolution (∼115 bp resolution) custom arrays covering the breakpoints on 1q for 11 samples, clustering of nine breakpoints was observed within a 12.5-kb region, of which eight were found in a 7-kb copy number variable region, whereas the remaining two breakpoints were colocated 1.4-Mb proximal. The commonly deleted region contains one miRNA (hsa-mir-1537), four transcribed ultra conserved region elements (uc.43-uc.46) and 130 protein coding genes including at least two bona fide tumor suppressor genes, EGLN1 (or PHD2) and FH. This finding further contributes to the delineation of the genomic profile of aggressive neuroblastoma, offers perspectives for the identification of genes contributing to the disease phenotype and may be relevant in the light of assessment of response to new molecular treatments.

Carbon dioxide does not affect the methylation status of prognostic important oncogenes Rassf1A and DCR2 in neuroblastoma cells

The aim of the current study was to investigate effects of CO(2) atmosphere, mimicking conditions of the pneumoperitoneum during laparoscopy, on epigenetic conditions of Rassf1A and DCR2 oncogenes in neuroblastoma cells. SH-SY5Y neuroblastoma cells were exposed to 100% CO(2) for 4 h. Cells were lysed 4, 8 and 168 h after exposure. After methylation analysis of Rassf1A and DCR2 with polymerase chain reaction, results were compared to those of physiologically incubated neuroblastoma cells. No significant changes were found after exposure to carbon dioxide compared to the control. Values of methylated Rassf1A were 12.6 +/- 1.1 versus 13.2 +/- 1.4 ng/microl in the controls, respectively (4 h after incubation), 12.6 +/- 1.2 versus 15.1 +/- 0.9 ng/microl (8 h) and 14.2 +/- 1.5 versus 11.7 +/- 1.3 ng/microl (168 h). DCR2 showed values of 4.6 +/- 0.5 versus 3.7 +/- 0.5 ng/microl (4 h), 3.8 +/- 0.5 versus 4.1 +/- 0.4 ng/microl (8 h) and 3.6 +/- 0.4 versus 3.8 +/- 0.5 ng/microl (168 h). Exposure of neuroblastoma cells to 100% CO(2) does not alter methylation of two prognostic relevant index genes. It seems therefore unlikely that effects on methylation levels within CO(2) pneumoperitoneum lead to epigenetic changes in neuroblastoma.

Genes Proximal and Distal to MYCN Are Highly Expressed in Human Neuroblastoma as Visualized by Comparative Expressed Sequence Hybridization

MYCN amplification is associated with poor prognosis in neuroblastoma disease. To improve our understanding of the influence of the MYCN amplicon and its corresponding expression, we investigated the 2p expression pattern of MYCN amplified (n = 13) and nonamplified (n = 4) cell lines and corresponding primary tumors (n = 3) using the comparative expressed sequence hybridization technique. All but one MYCN amplified cell line displayed overexpression at 2p. Expression peaks were observed frequently at 2pter and less frequently at 2p24 (MYCN locus), 2p23.3-23.2, and/or 2p23.1. Importantly, cell lines and two corresponding primary tumors displayed expression peaks at similar loci. No significant 2p24 expression level was observed for those cell lines displaying a low amplification rate (n = 3) by comparative genomic hybridization. Only the cell lines with an enhanced peak at 2p23.2-23.3 displayed coamplification of the ALK gene (2p23.2), reported to be associated with unfavorable prognosis. Finally, two of four cell lines without MYCN amplification, both derived from patients with poor outcome, also showed an expression peak at 2p23.2. These data indicate that, besides MYCN, other genes proximal and distal to MYCN are highly expressed in neuroblastoma. The prognostic significance of expression peaks at 2p23.2-23.3, independent of MYCN and ALK status, remains to be investigated.

Chromosome 1p and 11q Deletions and Outcome in Neuroblastoma—A Critical Review

Neuroblastoma is an embryonic neoplasm of the sympathetic nervous system that accounts for approximately 15 percent of all pediatric cancer fatalities. Genomic change in neuroblastoma has been shown to correlate with both behavior and outcome. More specifically, amplification of the MYCN oncogene occurs in about 20% of neuroblastoma patients and has been shown to provide important prognostic information. This correlation has typically led to a multidisciplinary approach in the treatment of this condition, including preventive screening, dose-intensive chemotherapy, stem-cell transplantation, targeted therapies (radiation, monoclonal antibodies, prodifferentiation agents), and monitoring of minimal disease. However, although MYCN has been associated with high-risk tumors, more than 60% of patients with aggressive disease do not exhibit this mutation, suggesting that other genetic mechanisms are involved in the pathophysiology of neuroblastoma. Consequently, the development of additional genetic markers could be useful not only in further understanding the molecular biology underlying these tumors, but also defining more effective therapy and aiding prognosis in this patient population. To this end, Attiyeh and colleagues published the results of their study investigating the effects of loss of heterozygosity (LOH) at chromosomes 1p and 11q on relapse and survival in neuroblastoma (1). LOH at chromosome arms 1p and 11q are noted frequently in neuroblastoma, and previous studies have suggested an association with high-risk features. Furthermore, 11q23 LOH is rarely observed in association with MYCN amplification. Given this fact, Attiyeh and colleagues hypothesized that 11q23 LOH could be a useful prognostic marker. In this study 915 samples of neuroblastoma were screened for LOH at chromosome bands 1p36 and 11q23, and associations with event-free and overall survival were performed. Results were as follows: patients in whom tumors showed 1p36 LOH had three-year event-free and overall survival rates of 47% and 64% respectively, as compared with 77% and 85%, respectively, in those patients who did not have 1p36 LOH. Similarly, unbalanced 11q LOH (unb11q LOH) was strongly associated with both decreased event-free and decreased overall survival. Analysis of the subgroup of cases without MYCN amplification showed that both 1p36 LOH and unb11q LOH were highly associated with decreases in both event-free and overall survival. More specifically, patients with unb11q LOH had three-year event-free and overall survival rates of 50% and 66%, respectively, as compared with 74% (P < 0.001) and 83% (P < 0.001) in those that did. Finally, in a multivariate analysis, unb11q LOH was found to be independently associated with decreased event-free survival. Based on these findings, the authors conclude that 1p36 and unb11q LOH are risk factors that should be incorporated into clinical trials of neuroblastoma. This study highlights the growing importance of genetic markers for use in stratification of tumor behavior. A number of markers including, MYCN amplification, HER2/neu over-expression, chromosome 17 gain, Trk expression, and CD44 genetic aberrations have proven useful, and the ability to detect risk factors at the time of diagnosis and tailor therapy accordingly could make the treatment of cancer both more effective and less toxic. Of greatest concern in neuroblastoma is the rare patient who despite a favorable clinical profile and no MYCN amplification progresses to high-risk disease. This study, although somewhat limited by the small numbers within subgroups, demonstrates that 1p36 LOH and unb11q LOH are strongly associated with outcome in patients with neuroblastoma. It is the hope of the authors’ that recognition and appreciation of these additional genetic markers will allow clinicians to more effectively tailor currently used prognostic schemes and treatment regimens.

Identification of 2 putative critical segments of 17q gain in neuroblastoma through integrative genomics

Partial gain of chromosome arm 17q is the most frequent genetic change in neuroblastoma (NB) and constitutes the strongest independent genetic factor for adverse prognosis. It is assumed that 1 or more genes on 17q contribute to NB pathogenesis by a gene dosage effect. In the present study, we applied chromosome 17 tiling path BAC arrays on a panel of 69 primary tumors and 28 NB cell lines in order to reduce the current smallest region of gain and facilitate identification of candidate dosage sensitive genes. In all tumors and cell lines with 17q gain, large distal segments were consistently present in extra copies and no interstitial gains were observed. In addition to these large regions of distal gain with breakpoints proximal to coordinate 44.3 Mb (17q21.32), smaller regions of gain (distal to coordinate 60 Mb at 17q24.1) were found superimposed on the larger region in a minority of cases. Positional gene enrichment analysis for 17q genes overexpressed in NB showed that dosage sensitive NB oncogenes are most likely located in the gained region immediately distal to the most distal breakpoint of the 2 breakpoint regions. Interestingly, comparison of gene expression profiles between primary tumors and normal fetal adrenal neuroblasts revealed 2 gene clusters on chromosome 17q that are overexpressed in NB, i.e. a region on 17q21.32 immediately distal to the most distal breakpoint (in cases with single regions of gain) and 17q24.1, a region coinciding with breakpoints leading to superimposed gain.

Methylation ofCASP8, DCR2, andHIN-1in Neuroblastoma Is Associated with Poor Outcome

Epigenetic aberrations have been shown to play an important role in the pathogenesis of most cancers. To investigate the clinical significance of epigenetic changes in neuroblastoma, we evaluated the relationship between clinicopathologic variables and the pattern of gene methylation in neuroblastoma cell lines and tumors. Methylation-specific PCR was used to evaluate the gene methylation status of 19 genes in 14 neuroblastoma cell lines and 8 genes in 70 primary neuroblastoma tumors. Associations between gene methylation, established prognostic factors, and outcome were evaluated. Log-rank tests were used to identify the number of methylated genes that was most predictive of overall survival. Epigenetic changes were detected in the neuroblastoma cell lines and primary tumors, although the pattern of methylation varied. Eight of the 19 genes analyzed were methylated in >70% of the cell lines. Epigenetic changes of four genes were detected in only small numbers of cell lines. None of the cell lines had methylation of the other seven genes analyzed. In primary neuroblastoma tumors, high-risk disease and poor outcome were associated with methylation of DCR2, CASP8, and HIN-1 individually. Although methylation of the other five individual genes was not predictive of poor outcome, a trend toward decreased survival was seen in patients with a methylation phenotype, defined as > or =4 methylated genes (P = 0.055). Our study indicates that clinically aggressive neuroblastoma tumors have aberrant methylation of multiple genes and provides a rationale for exploring treatment strategies that include demethylating agents.

Genome-Wide Analysis of Neuroblastomas using High-Density Single Nucleotide Polymorphism Arrays

BackgroundNeuroblastomas are characterized by chromosomal alterations with biological and clinical significance. We analyzed paired blood and primary tumor samples from 22 children with high-risk neuroblastoma for loss of heterozygosity (LOH) and DNA copy number change using the Affymetrix 10K single nucleotide polymorphism (SNP) array.FindingsMultiple areas of LOH and copy number gain were seen. The most commonly observed area of LOH was on chromosome arm 11q (15/22 samples; 68%). Chromosome 11q LOH was highly associated with occurrence of chromosome 3p LOH: 9 of the 15 samples with 11q LOH had concomitant 3p LOH (P = 0.016). Chromosome 1p LOH was seen in one-third of cases. LOH events on chromosomes 11q and 1p were generally accompanied by copy number loss, indicating hemizygous deletion within these regions. The one exception was on chromosome 11p, where LOH in all four cases was accompanied by normal copy number or diploidy, implying uniparental disomy. Gain of copy number was most frequently observed on chromosome arm 17q (21/22 samples; 95%) and was associated with allelic imbalance in six samples. Amplification of MYCN was also noted, and also amplification of a second gene, ALK, in a single case.ConclusionsThis analysis demonstrates the power of SNP arrays for high-resolution determination of LOH and DNA copy number change in neuroblastoma, a tumor in which specific allelic changes drive clinical outcome and selection of therapy.

Full Cytogenetic Characterization of a New Neuroblastoma Cell Line with a Complex 17q Translocation

Recent studies have shown that structural abnormalities of chromosome 17 resulting in gain of material are the most frequent genetic changes in neuroblastoma. We have established a new neuroblastoma cell line from a patient whose disease had evolved from stage 4s to 4, without evidence of deletion of the short arm of chromosome 1 and MYCN amplification, which are considered the most typical genetic indicators of aggressive disease. The cytogenetic study allowed a full characterization of the chromosome changes, and revealed a complex translocation of chromosome 17 leading to a derivative marker which may be described as follows: der(11)t(11;17)(p15;q12)t(11;17)(q22;q12). This resulted in a gain of part of the long arms of chromosome 17, which was recently associated with poor prognosis.

Molecular cytogenetic delineation of 17q translocation breakpoints in neuroblastoma cell lines.

It has recently been recognized that unbalanced translocations resulting in the gain of material from 17q are the most common chromosomal changes in neuroblastoma. These rearrangements are associated with established indicators of bad prognosis and poor patient survival. We have used 13 fluorescence in situ hybridization (FISH) probes to map 12 translocation breakpoints on 17q in 10 neuroblastoma cell lines, identifying at least seven different breakpoints, all localized within the proximal half of 17q (268-369 cR, 53-68 cM). These results suggest that the dosage of a gene, or genes, in 17q22-qter is responsible for the clinical effects of 17q gain, rather than the disruption of a specific gene. This region contains two genes, nm23-H1 and NGFR, already implicated in neuroblastoma biology.

Sensitive and reliable detection of genomic imbalances in human neuroblastomas using comparative genomic hybridisation analysis.

Deletions of the short arm of chromosome 1, extra copies of chromosome 17q and MYCN amplification are the most frequently encountered genetic changes in neuroblastomas. Standard techniques for detection of one or more of these genetic changes are karyotyping, FISH analysis and LOH analysis by Southern blot or PCR. Each of these techniques has its own particular limitations. More recently, comparative genomic hybridisation (CGH) was introduced for detection of genomic imbalances including deletions, duplications and gene amplification. We evaluated the sensitivity and reliability of CGH for detection of the most frequently encountered genetic changes in neuroblastoma. For this purpose a panel of well-characterised neuroblastoma cell lines as well as a series of 11 primary neuroblastomas was analysed. Our results show that CGH is a valuable tool for the genetic characterisation of neuroblastomas, both for the detection of frequently occurring genomic imbalances and for the identification of previously unnoticed genetic changes.

Comparative genomic hybridization analysis of human neuroblastomas: Detection of distal 1p deletions and further molecular genetic characterization of neuroblastoma cell lines

Deletions of the short arm of chromosome 1 and MYCN amplification are the most frequently encountered genetic changes in disseminated neuroblastomas and neuroblastoma cell lines. Different strategies have been followed for detection of these and other genomic changes in neuroblastoma including karyotyping, FISH, and LOH, each with its own limitations. Here we report upon the evaluation of comparative genomic hybridization (CGH) in the analysis of neuroblastoma cell lines, with the emphasis on the assessment of the reliability of CGH for the detection of distal 1p deletions. We have analyzed seven neuroblastoma cell lines for which the 1p status was previously studied in detail using FISH and LOH. Our results show that CGH allows reliable detection of distal 1p deletions, including a small interstitial deletion in cell line SK-N-AS. Furthermore, CGH also allows the detection of chromosomal imbalances which would otherwise remain undetected, and provides useful information for further molecular characterization of chromosomal imbalances.

COMPARATIVE GENOMIC HYBRIDIZATION (CGH) ANALYSIS OF NEUROBLASTOMAS—AN IMPORTANT METHODOLOGICAL APPROACH IN PAEDIATRIC TUMOUR PATHOLOGY

Comparative genomic hybridization (CGH) was applied to 35 neuroblastomas to obtain a global view of genetic imbalances. Results were validated by means of Southern blot hybridization (detection of N-myc amplification), loss of heterozygosity (LOH) studies (detection of deletion 1p), and interphase cytogenetics [dual labelling fluorescence in situ hybridization (FISH) of centromeric 17 and erbB-2]. CGH allowed sensitive detection of N-myc amplification and chromosome 1p deletion, representing the most established prognostic markers of neuroblastoma. In addition, a high rate of chromosome 17 aberrations (63 per cent) with possible prognostic relevance was observed. Previously unreported high level copy number increases indicating oncogene amplification were mapped to chromosome subbands 2p13–14 and 3q24–26. Other recurrent regional chromosomal aberrations were localized on 11q, 12q, 13q, 14q, and 15q. CGH results were fully consistent with data of Southern blot analysis and LOH study, as well as interphase cytogenetics. These results show that CGH is a sensitive method for the detection of all prognostically relevant genetic alterations in neuroblastomas; that CGH considerably simplifies the detection of these alterations, resulting in a single methodological approach; and that CGH is a powerful tool to elucidate previously unknown genetic changes in neuroblastomas. © 1997 by John Wiley & Sons, Ltd.

Comparative genomic hybridization (CGH) analysis of neuroblastomas--an important methodological approach in paediatric tumour pathology.

Comparative genomic hybridization (CGH) was applied to 35 neuroblastomas to obtain a global view of genetic imbalances. Results were validated by means of Southern blot hybridization (detection of N-myc amplification), loss of heterozygosity (LOH) studies (detection of deletion 1p), and interphase cytogenetics [dual labelling fluorescence in situ hybridization (FISH) of centromeric 17 and erbB-2]. CGH allowed sensitive detection of N-myc amplification and chromosome 1p deletion, representing the most established prognostic markers of neuroblastoma. In addition, a high rate of chromosome 17 aberrations (63 per cent) with possible prognostic relevance was observed. Previously unreported high level copy number increases indicating oncogene amplification were mapped to chromosome subbands 2p13-14 and 3q24-26. Other recurrent regional chromosomal aberrations were localized on 11q, 12q, 13q, 14q, and 15q. CGH results were fully consistent with data of Southern blot analysis and LOH study, as well as interphase cytogenetics. These results show that CGH is a sensitive method for the detection of all prognostically relevant genetic alterations in neuroblastomas; that CGH considerably simplifies the detection of these alterations, resulting in a single methodological approach; and that CGH is a powerful tool to elucidate previously unknown genetic changes in neuroblastomas.

An immunohistochemical analysis of mdr-1 and bcl-2 expressions in neuroblastoma

Among the differentiation-related changes in neuroblastoma are expressions of mdr-1 and bcl-2, which may be potentially related to the resistance to anticancer chemotherapy. In the present study, the authors performed an immunohistochemical analysis of mdr-1 and bcl-2 expressions in 30 neuroblastomas using monoclonal anti-P-glycoprotein(mdr-1 product) antibody and monoclonal anti-bcl-2 antibody to investigate the significance of their expression. The overall incidence of mdr-1 and bcl-2 expressions were 53.3% (16/30) and 93.3% (28/30), respectively. The expressions of mdr-1 and bcl-2 didn't seem to be related to the status of preoperative chemotherapy or stage of disease. The expression of mdr-1 was closely related to the differentiation of tumor cells (p < 0.01), especially to the neuronal differentiation. The bcl-2 expression was so common that it seemed to be indigenous to this neoplasm. The overall findings suggested that the expression of mdr-1 is one of the differentiation markers, while bcl-2 expression may partly explain the reasons for the relatively poor prognosis of neuroblastoma by the resistance to anticancer chemotherapy, which is a major therapeutic tool for this peculiar neoplasm.

MEASUREMNT OF MCV

British Journal of HaematologyVolume 88, Issue 2 p. 445-447 Free Access MEASUREMNT OF MCV S. R. Smith, S. R. Smith Department of Haematology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LPSearch for more papers by this authorM. M. Reid, M. M. Reid Department of Haematology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LPSearch for more papers by this author S. R. Smith, S. R. Smith Department of Haematology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LPSearch for more papers by this authorM. M. Reid, M. M. Reid Department of Haematology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LPSearch for more papers by this author First published: October 1994 https://doi.org/10.1111/j.1365-2141.1994.tb05056.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. REFERENCES Frankilin, I.M. & Pritchard, J. (1983) Detection of bone marrow invasion by neuroblastoma is improved by sampling at two sites with both aspirates and trephine biopsies. Journal of Clinical Pathology, 36, 1215– 1218. Mills, A.E. & Bird, A.R. (1986) Bone marrow changes in neuroblastoma. Pediatric Pathology, 5, 225– 234. Citing Literature Volume88, Issue2October 1994Pages 445-447 ReferencesRelatedInformation