Neuroblastic Tumors Research Articles

CCM2 Mediates Death Signaling by the TrkA Receptor Tyrosine Kinase

The TrkA receptor tyrosine kinase is crucial for differentiation and survival of nerve-growth-factor-dependent neurons. Paradoxically, TrkA also induces cell death in pediatric tumor cells of neural origin, via an unknown mechanism. Here, we show that CCM2, a gene product associated with cerebral cavernous malformations, interacts with the juxtamembrane region of TrkA via its phosphotyrosine binding (PTB) domain and mediates TrkA-induced death in diverse cell types. Both the PTB and Karet domains of CCM2 are required for TrkA-dependent cell death, such that the PTB domain determines the specificity of the interaction, and the Karet domain links to death pathways. Downregulation of CCM2 in medulloblastoma or neuroblastoma cells attenuates TrkA-dependent death. Combined high expression levels of CCM2 and TrkA are correlated with long-term survival in a large cohort of human neuroblastoma patients. Thus, CCM2 is a key mediator of TrkA-dependent cell death in pediatric neuroblastic tumors.

Neurological complications of neuroblastic tumors: experience of a single center

This study aims to evaluate the prevalence and clinical characteristics of neurological complications in patients with newly diagnosed neuroblastic tumors (NT). Hospital file search was performed in patients with NT, and neurological complications, clinical, and treatment features were analyzed. Out of 523 patients with NT, 19 patients had Horner's syndrome, 9 patients had opsoclonus-myoclonus-ataxia syndrome (OMA), 11 patients had central nervous system (CNS) involvement, and 49 patients had spinal cord compression (SCC) at diagnosis. During follow-up, seven more patients had CNS metastases. Survival rates were poor in patients with CNS involvement; all died at a median of 7.9 months after diagnosis. The neurological symptoms and signs of patients with SCC were mild, moderate, and severe in 13, 9, and 22 patients, respectively. Sphincter deficiency and sensory loss were diagnosed in 52.3% and 43.2% of patients. The neurological deficits of 11/17 patients who had symptoms less than 4 weeks were completely resolved or improved. The incidence of sequelae after laminectomy, radiotherapy, and chemotherapy were 46.2%, 66.6%, and 13.6%, respectively. The prevalence rates of Horner's syndrome, OMA, CNS metastasis, and SCC were found to be 3.6%, 1.8%, 2.2%, and 9.4%, respectively. Metastasis to the CNS indicated a very poor prognosis. No differences in neurological improvement in patients with SCC were found between those treated with radiotherapy, laminectomy, or chemotherapy alone, but laminectomy and radiotherapy caused significant late sequelae. Early diagnosis and proper management is critical to avoid long-term sequelae in patients with SCC.

Constitutional retinoblastoma gene deletion in Egyptian patients

Retinoblastoma is a neuroblastic tumor of childhood with an incidence of 1: 20 000. Retinoblastoma gene (Rb1) is a tumor suppressor gene that is located on the long arm of chromosome 13 at region 14. This study was to evaluate the constitutional monoallelic Rb1 deletion among retinoblastoma families. Nine families with an affected Rb proband were evaluated. Clinical examination, pedigree analysis, and complete eye examination were given to patients, their sibs and parents. Standard cytogenetic and fluorescence in situ hybridization (FISH) analyses were carried out for all of them. Also, two sib fetuses were tested for Rb1 deletion. No dysmorphic features were detected in any patient. Developmental milestones were within normal limit except in one proband who had a mild delay. The age of onset ranged from one month to 4 years. Positive family history was found in two families. In one, the father and 3 sibs had retinoblastoma, and in the other, 2 sibs were affected, but the parents were free. Chromosomal study revealed no abnormalities in all parents and sibs. Two patients had mosaic chromosome 13 abnormalities, 46,XY/46,XY,del(13)(pter-->q14:) and 46,XX/46,inv(13)(q14q22). FISH analysis detected mosaic Rb1 deletion in two patients and excluded Rb1 deletion in two fetuses. The detection of genetic alterations affecting the Rb1 locus is important for the establishment of carriers, and prenatal and presymptomatic diagnosis. The search for deleted Rb1 mosaic cell lines is important for genetic counseling. Germline mutation may be considered as genetic transmission method of the Rb1 gene.

Ganglioneuroma of the retroperitoneum presenting as a pediatric renal mass

Ganglioneuroma is the benign representative of peripheral neuroblastic tumors, with localized and predominant thoracic presentations in older children. They often have an excellent outcome with surgery alone. A 12-year-old girl presented with an incidentally detected abdominal mass, which was clinicoradiologically a renal mass. Laparotomy revealed a mass adherent to the anterior surface of the right kidney. The mass was carefully dissected out, sacrificing a portion of the inferior vena cava. Histopathological diagnosis was that of a ganglioneuroma. She was kept under follow up.

The calcium‐sensing receptor and parathyroid hormone‐related protein are expressed in differentiated, favorable neuroblastic tumors

Differentiated histopathology is a favorable prognostic factor in neuroblastic tumors, and molecular pathways underlying neuroblastoma differentiation can be modulated pharmacologically. The calcium-sensing receptor (CaR) and parathyroid hormone-related protein (PTHrP) regulate differentiation processes in some cellular contexts. CaR is up-regulated when neural stem cells are specified to the oligodendrocyte lineage and regulates PTHrP production in astrocytes. The objective of the current study was to assess whether CaR and PTHrP participate in neuroblastoma differentiation pathways. CaR and PTHrP messenger RNA (mRNA) and protein expression were analyzed in neuroblastic tumors, and correlation with prognostic factors was assessed. CaR and PTHrP expression levels were analyzed in neuroblastoma cell lines treated with all-trans-retinoic acid or 5-bromo-2'-deoxyuridine (BrdU). CaR expression was correlated with favorable histology, age at diagnosis <1 year, low clinical stage, and low clinical risk. CaR was absent in undifferentiated neuroblasts and was expressed in differentiating neuroblasts. CaR and PTHrP were highly expressed in ganglion and in Schwann-like cells. PTHrP mRNA levels were higher in ganglioneuroblastomas and ganglioneuromas than in neuroblastomas (P < .0001). Both genes were up-regulated in neuroblastomas with treatment-induced maturation features. CaR, but not PTHrP, was up-regulated at early phases of in vitro neuronal differentiation induction. Substrate-adherent, non-neuronal cell lines displayed the highest PTHrP levels among the neuroblastoma cell lines examined. The up-regulation of PTHrP and of 2 glial differentiation markers was observed in 2 cell lines that were treated with BrdU, whereas CaR was induced in only 1 cell line. CaR and PTHrP were expressed in differentiated, favorable neuroblastic tumors, and both genes were up-regulated by inducing differentiation.

Expression of endothelin system in neuroblastic tumors: close association of endothelin-1 and endothelin B receptor expression with differentiation of tumor cells

Although a critical role of the endothelin (ET) system in differentiation of neural crest cells has been reported, implication of the ET system in human neuroblastic tumors has not been fully elucidated. We immunohistochemically examined for localization of ET-1, ET-3, ET-A receptor (ET-A), and ET-B receptor (ET-B) in 24 ganglioneuromas, 8 ganglioneuroblastomas, 37 neuroblastomas, 14 normal sympathetic ganglia, and 10 fetal adrenal glands with regard to neuroblastic cell differentiation. Neuroblasts in fetal adrenal glands expressed ET-B (100%) alone. Immature ganglionic cells in sympathetic ganglia of fetus frequently expressed ET-1 (86%) and ET-B (100%), while ET-A was occasionally detected (28%). Ganglionic cells of mature adult ganglia consistently harbored ET-1 (100%) and, infrequently, ET-3 (21%) or ET-B (29%). Expression of ET-1 and ET-B was closely associated with tumor cell differentiation: the expression frequency of ET-1 or ET-B was 16% or 46% in neuroblastomas; 100% or 88% in ganglioneuroblastomas; and 96% or 92% in ganglioneuromas. In contrast, ET-3 and ET-A showed no association with tumor cell differentiation: the expression frequency of ET-3 or ET-A was 26% or 14% in neuroblastomas; 63% or 13% in ganglioneuroblastomas; and 29% or 21% in ganglioneuromas. In conclusion, ET-1 and ET-B are expressed with differentiation of neuroblastic tumors.

MYCN gene amplification and DNA ploidy in peripheral neuroblastic tumors

e22123 Background: Neuroblastoma is a neuroblastic tumor of the primordial crest cells which are precursors of the sympathetic nervous system and is the most common extracranial solid tumor of childhood comprising between 8 and 10% of all childhood cancers. Neuroblastoma is characterized by a diverse clinical and biological behavior The spectrum of clinical behavior suggests that genetic, biological and morphological features may be useful markers to stratify children with this disease for the most appropriate management Fluorescence in situ hybridization (FISH) is considered the best approach for detection of MYCN amplification because it can detect small copy number gains and copy number heterogeneity among tumor cells. Also, it can determine the source of amplified MYCN signal, whether extrachromosomal double minutes, expanded intrachromosomal region or chromosome 2 aneuploidy. Methods: 30 cases of peripheral neuroblastic tumors were analysed for MYCN oncogene copy number and DNA ploidy using FISH. The 30 cases were divided into: 25 cases of neuroblastoma, 2 cases of ganglioneuroblastoma intermixed, and 3 cases of ganglioneuroma. Results: MYCN oncogene was amplified in 8 out of 30 cases (27.5%). 3 cases showed double minutes, 3 cases showed homogenously staining regions and 2 cases showed both forms of amplification. As regard DNA ploidy, 18 cases were diploid and 12 cases were hyperdiploid. MYCN oncogene amplification was significantly correlated with unfavorable histology, advanced tumor stage increased recurrence and poor survival. Also ploidy was associated with increased recurrence and reduced survival. And so, MYCN oncogene amplification and DNA ploidy were poor prognostic markers and it is recommended that assessment of these factors should be routine in the management of any case of neuroblastoma. Conclusions: 1) MYCN gene amplificahion and DNA plidy are poor prognostic markers 2) They should be measured in every case of peripheral neuroblastic tumors. 3) FISH should be used in the detechion of MYCN oncogene amplification and DNA ploidy No significant financial relationships to disclose.

Staging of common paediatric tumours

Imaging at diagnosis in oncology patients is crucial as it provides strong arguments for differential diagnosis, anatomical location, biopsy guidance, and local and distant metastases assessment. Most paediatric cancers are treated according to international protocols and trials that allow pooling of results of multiple centres, hence providing sufficient data to obtain significant differences between various treatment arms. This strategy allowed national and international groups (notably the International Society of Paediatric Oncology [SIOP] and the Children’s Oncology Group [COG]) to significantly increase the overall survival of affected children. Nevertheless, this is only possible if the protocol stratification is correctly followed, i.e., if the appropriate inclusion criteria are precisely used. Tumour stage is not the only inclusion/stratification criterion used, since treatments are also decided on the basis of biology (tumour markers), cyto/histological data (histological risk group, cytology or histology of bone marrow, lymph nodes and CSF) and, increasingly, on tumour genetics (chromosomal abnormalities, gene deletion, translocation, amplification). However, imaging is still one of the most important issues. Therefore, depending on tumour type, radiologists should be aware of the anatomical regions to analyze, the best imaging techniques to choose, and the appropriate diagnostic criteria. This information may be obtained from the literature when based on well-designed studies with pathological correlations. However, many staging criteria are also protocol specific and available only in the dedicated protocol imaging guidelines. In an ideal world, these guidelines should always be written by paediatric radiologists (after discussion with paediatricians, surgeons and radiotherapists) and should be available for any new treatment protocol. Actually, this is the only condition to unify the staging, and, therefore the stratification and treatment results. Prospective or retrospective central image review is increasingly used in oncology trials. As the quality of the review process is linked to the quality of the images, all imaging data of paediatric cancers should always be stored in DICOM format (on CD-ROM or on PACS, when available). Haematological malignancies (leukaemia, lymphoma) account for about 40% of all paediatric neoplasms and CNS tumours for about a further 25%. Among the remaining 35%, the most frequent paediatric solid neoplasms are neuroblastic tumours (neuroblastoma, ganglioneuroblastoma; representing about 9% of all paediatric cancers), renal tumours (about 6%; mostly Wilms tumour), soft-tissue sarcomas (about 5%; more than half being rhabdomyosarcoma), bone tumours (5%; mainly osteosarcoma and Ewing sarcoma), retinoblastoma (2%) and malignant gonadal and germ-cell tumours (3.5%). Carcinomas (adrenocortical, thyroid, nasopharyngeal, etc) and melanomas are rare (2.5%) compared to adults. Malignant hepatic tumours (hepatoblastoma, hepatocellular carcinoma, embryonal sarcoma, etc) only account for about 1% of all paediatric cancers. The aim of this review is to underline the imaging key points for disease staging of the most common solid tumours typically observed in children, i.e., Wilms tumour, neuroblastoma and rhabdomyosarcoma. Pediatr Radiol (2009) 39 (Suppl 3):S482–S490 DOI 10.1007/s00247-009-1193-x

Expression of VEGF and bcl-2 in Olfactory Neuroblastoma: Association with Microvessel Density

Introduction: Olfactory neuroblastoma (ONB) is a rare malignant tumor that is believed to arise from the olfactory epithelium in the vault of the nasal cavity. Neoangiogenesis plays a fundamental role in the pathogenesis and progression of malignant solid tumors and this process is controlled by angiogenic growth factors. A number of angiogenic factors, including vascular endothelial growth factor (VEGF), have been shown to be expressed in neuroblastic tumors. In hypoxic conditions, VEGF expression is regulated via hypoxia-inducible factor (HIF)-1a and bcl-2. Activation of the VEGF receptors (VEGF-R1/R2) by VEGF promotes neoangiogenesis in various malignant tumors. Methods: Expression of HIF-1a, VEGF, VEGF-R1, VEGF-R2, and bcl-2 was studied by immunohistochemistry in a series of 19 olfactory neuroblastoma samples. Data were correlated with microvessel density, proliferative activity, and apoptosis in the specimens, and survival analysis was performed to investigate the prognostic value of the examined factors. Results: Immunohistochemical analysis revealed robust expression of HIF-1a, VEGF, VEGF-R1/-R2, and bcl-2 in ONB. A significant positive correlation between the expression levels of VEGF and bcl-2 was found. Expression of both factors was associated with microvessel density of the tumors. Survival analysis did not reveal any prognostic significance for the tested factors. Conclusion: Expression of HIF-1a, VEGF, VEGF-R1/-R2, and bcl-2 may play a functional role in ONB pathogenesis. Our data suggest that bcl-2 regulates VEGF expression, and both factors may promote angiogenesis in ONB. Thus, these factors represent potential targets for antiangiogenic treatment strategies in the therapy of ONB.

The low‐affinity neurotrophin receptor, p75, is upregulated in ganglioneuroblastoma/ganglioneuroma and reduces tumorigenicity of neuroblastoma cells in vivo

Neuroblastoma, the most common extracranial tumor of childhood, is derived from neural crest progenitor cells that fail to differentiate along their predefined route to sympathetic neurons or sympatho-adrenergic adrenal cells. Although expression of the high-affinity neurotrophin receptors, TrkA and TrkB, is of major importance in neuroblastoma, the significance of the expression of the low-affinity neurotrophin receptor, p75, is unclear. Here, we analyzed immunohistochemically expression of p75 on a tissue microarray of 93 primary neuroblastic tumors and assessed the functional consequences of p75 expression in neuroblastoma cell lines. We found the p75 receptor protein to be expressed in neuroblastic cells of ganglioneuromas/ganglioneuroblastomas as well as differentiating neuroblastomas, but not in poorly differentiated neuroblastomas. In an unrelated cohort of 110 neuroblastic tumors, p75 mRNA expression levels correlated with differentiation, and patients with tumors that expressed p75 at high levels had an increased event-free and overall survival. In addition, we did not detect p75 expression in 8 established neuroblastoma cell lines examined with FACS analysis. These cell lines exhibited an undifferentiated morphology, and were all derived from aggressive, high-stage neuroblastomas. Ectopic p75 expression in the SH-SY5Y neuroblastoma cell line significantly reduced proliferation, increased the fraction of apoptotic cells in vitro and resulted in a loss of tumorigenicity in nude mice. Taken together, our data suggest that expression of the p75 low-affinity neurotrophin receptor is correlated with a reduced level of tumorigenicity, and that induction of p75 expression may be an option to revert features of an aggressive tumor phenotype.

Lysine-Specific Demethylase 1 Is Strongly Expressed in Poorly Differentiated Neuroblastoma: Implications for Therapy

Aberrant epigenetic changes in DNA methylation and histone acetylation are hallmarks of most cancers, whereas histone methylation was previously considered to be irreversible and less versatile. Recently, several histone demethylases were identified catalyzing the removal of methyl groups from histone H3 lysine residues and thereby influencing gene expression. Neuroblastomas continue to remain a clinical challenge despite advances in multimodal therapy. Here, we address the functional significance of the chromatin-modifying enzyme lysine-specific demethylase 1 (LSD1) in neuroblastoma. LSD1 expression correlated with adverse outcome and was inversely correlated with differentiation in neuroblastic tumors. Differentiation of neuroblastoma cells resulted in down-regulation of LSD1. Small interfering RNA-mediated knockdown of LSD1 decreased cellular growth, induced expression of differentiation-associated genes, and increased target gene-specific H3K4 methylation. Moreover, LSD1 inhibition using monoamine oxidase inhibitors resulted in an increase of global H3K4 methylation and growth inhibition of neuroblastoma cells in vitro. Finally, targeting LSD1 reduced neuroblastoma xenograft growth in vivo. Here, we provide the first evidence that a histone demethylase, LSD1, is involved in maintaining the undifferentiated, malignant phenotype of neuroblastoma cells. We show that inhibition of LSD1 reprograms the transcriptome of neuroblastoma cells and inhibits neuroblastoma xenograft growth. Our results suggest that targeting histone demethylases may provide a novel option for cancer therapy.

Lysine-Specific Demethylase 1 Is Strongly Expressed in Poorly Differentiated Neuroblastoma: Implications for Therapy

Aberrant epigenetic changes are hallmarks of most cancers. Recently, a new class of histone modifying enzymes, demethylases, was identified catalyzing the removal of methyl groups from histone H3 lysine residues. Here, we address the functional significance of lysine-specific demethylase 1 (LSD1) in neuroblastoma. LSD1 expression correlated with adverse outcome and was inversely correlated with differentiation in neuroblastic tumors. Differentiation of neuroblastoma cells resulted in down-regulation of LSD1. Small interfering RNA-mediated knockdown of LSD1 decreased cellular growth, induced expression of differentiation-associated genes, and increased target gene-specific H3K4 methylation. LSD1 inhibition using monoamine oxidase inhibitors resulted in an increase of global H3K4 methylation, growth inhibition of neuroblastoma cells in vitro and reduced xenograft growth in vivo. To prove specificity of LSD1 targeting therapy in vivo, a transgenic mouse for tetracycline inducible expression of a shRNA against LSD1 was generated. This model is now used to simulate therapeutic LSD1 inhibition in vivo. Here, we provide first evidence that a histone demethylase, LSD1, is involved in maintaining the undifferentiated, malignant phenotype of neuroblastoma cells. Our results suggest that targeting histone demethylases may provide a novel option for cancer therapy.

N-myc induces transformation of neural crest stem cells in vitro and in vivo

Cumulating evidence suggests that neuroblastoma (NB) originates from neural crest stem cells (NCSC) of the sympathoadrenal lineage. Pluripotency of NCSC is documented by the ability to differentiate into muscle cells, chromaffin cells, neurons and glial cells, as well as melanocytes, cartilage and bone. To characterize the NCSC population, a cell line is required that can be maintained for many passages, and which retains pluripotency as well as self renewal capacity. We previously established a multipotent NCSC line, JoMa1, which is kept in an undifferentiated state by conditional expression of c-Myc and which can be differentiated into the above mentioned cell types. N-myc has been shown to promote cell cycle progression in NB cells in vitro and transgenic overexpression of N-myc is sufficient to induce neuroblastoma-like tumors in mice. Still, the origin of neuroblastoma could not be clearly assigned to a defined cell population. To address this question, we established JoMa1 cells with stable ectopic expression of N-Myc. JoMa1-Nmyc were able to grow in cell culture without depending on c-myc expression. Subcutaneous injection of JoMa1-Nmyc into nude mice caused the formation of NB-like tumors. Interestingly, treatment of xenografted JoMa1 using a Myc-inhibitor inhibited cell proliferation in vitro. Thus, we here show for the first time that transformed NCSC cells can give rise to neuroblastic tumors and support the notion that NCSC are the precursor cells of neuroblastoma. We now aim to characterize the tumorigenicity of JoMa1-Nmyc in a syngeneic mouse model and to identify the genomic changes caused by N-myc driven transformation of JoMa1.

Landmarking and segmentation of computed tomographic images of pediatric patients with neuroblastoma

Segmentation and landmarking of computed tomographic (CT) images of pediatric patients are important and useful in computer-aided diagnosis, treatment planning, and objective analysis of normal as well as pathological regions. Identification and segmentation of organs and tissues in the presence of tumors is difficult. Automatic segmentation of the primary tumor mass in neuroblastoma could facilitate reproducible and objective analysis of the tumor's tissue composition, shape, and volume. However, due to the heterogeneous tissue composition of the neuroblastic tumor, ranging from low-attenuation necrosis to high-attenuation calcification, segmentation of the tumor mass is a challenging problem. In this context, we explore methods for identification and segmentation of several abdominal and thoracic landmarks to assist in the segmentation of neuroblastic tumors in pediatric CT images. Methods are proposed to identify and segment automatically peripheral artifacts and tissues, the rib structure, the vertebral column, the spinal canal, the diaphragm, and the pelvic surface. The results of segmentation of the vertebral column, the spinal canal, the diaphragm and the pelvic girdle are quantitatively evaluated by comparing with the results of independent manual segmentation performed by a radiologist. The use of the landmarks and removal of several tissues and organs assisted in limiting the scope of the tumor segmentation process to the abdomen, and resulted in the reduction of the false-positive error rates by 22.4%, on the average, over ten CT exams of four patients, and improved the result of segmentation of neuroblastic tumors.

VIP hypersecretion as primary or secondary syndrome in neuroblastoma: A retrospective study by the Société Française des Cancers de l'Enfant (SFCE)

Neuroblastic tumors (NTs) are occasionally associated with watery diarrhea, due to Vasoactive Intestinal Peptide (VIP) secretion. Most reports are single cases and suggest a great homogeny within this sub-group of NTs. We conducted a retrospective analysis of the French experience of NTs associated with watery diarrhea due to VIP-secretion. VIP secretion was confirmed by seric dosage and/or immunohistochemistry. Twenty-two patients met the diagnostic criteria between 1988 and 2007. Most of patients suffered from weight loss and metabolic disorders. In 16 cases, digestive symptoms preceded the diagnosis of the tumor ("Primary VIP secreting NTs"); 15 were localized and all showed a differentiated histology. Interestingly, in another 6 patients with high-risk NT, diarrhea occurred at the time of chemotherapy or retinoic acid therapy ("Secondary VIP secreting NTs"). Differentiation in response to treatment was documented in 4 cases. In all cases, only surgical excision of the tumor was able to control the digestive symptoms. Twenty children are alive and 13 are disease-free. VIP secreting NTs are usually associated with differentiation; they can also secondarily arise from a high-risk tumor upon treatment. Primary surgery constitutes first-line treatment.

Landmarking and Segmentation of 3D CT Images

Segmentation and landmarking of computed tomographic (CT) images of pediatric patients are important and useful in computer-aided diagnosis (CAD), treatment planning, and objective analysis of normal as well as pathological regions. Identification and segmentation of organs and tissues in the presence of tumors are difficult. Automatic segmentation of the primary tumor mass in neuroblastoma could facilitate reproducible and objective analysis of the tumor's tissue composition, shape, and size. However, due to the heterogeneous tissue composition of the neuroblastic tumor, ranging from low-attenuation necrosis to high-attenuation calcification, segmentation of the tumor mass is a challenging problem. In this context, methods are described in this book for identification and segmentation of several abdominal and thoracic landmarks to assist in the segmentation of neuroblastic tumors in pediatric CT images. Methods to identify and segment automatically the peripheral artifacts and tissu s, the rib structure, the vertebral column, the spinal canal, the diaphragm, and the pelvic surface are described. Techniques are also presented to evaluate quantitatively the results of segmentation of the vertebral column, the spinal canal, the diaphragm, and the pelvic girdle by comparing with the results of independent manual segmentation performed by a radiologist. The use of the landmarks and removal of several tissues and organs are shown to assist in limiting the scope of the tumor segmentation process to the abdomen, to lead to the reduction of the false-positive error, and to improve the result of segmentation of neuroblastic tumors. Table of Contents: Introduction to Medical Image Analysis / Image Segmentation / Experimental Design and Database / Ribs, Vertebral Column, and Spinal Canal / Delineation of the Diaphragm / Delineation of the Pelvic Girdle / Application of Landmarking / Concluding Remarks

Analysis of biological prognostic factors using tissue microarrays in neuroblastic tumors

Neuroblastic tumors (NT) are pediatric neoplasms with a heterogeneous genetic profile. They present genotypic alterations of prognostic value, the study of which is mandatory in designing therapeutic management. Tissue microarrays (TMA) from paraffin material allow the analysis of a large number of cases with minimal costs. The main purpose of the present study is to analyze specific genetic markers of neuroblastic tumors included in TMAs and determine their prognostic value. We compare the results obtained by different molecular techniques at different substrates to evaluate the feasibility of these assays. One hundred thirty-nine samples were included in four different TMAs. We performed FISH assays to determine the status of MYCN gene, 1p36 region and 17q23 arm. The prognostic value of the genetic markers as well as the statistical correlation among clinical variables and outcome were analyzed by SPSS. MYCN amplification was detected in 35.3% of the cases, whereas 1p36 deletion and 17q23 gain was observed in 46.8% and 58.3% of the cases, respectively. An adverse prognosis was noted among these patients. Other adverse factors were age (>18 months) as well as high stage of disease (stage 4). Phenotypic signs of differentiation correlated with good outcome. Retrospective studies using paraffin-embedded tissues assembled in TMA are a useful tool for the analysis of prognostic factors in NT.

Ganglioneuroma of the mandible resulting from metastasis of neuroblastoma

Neuroblastoma, ganglioneuroblastoma and ganglioneuroma are neuroblastic tumours derived from primordial neural crest tissue. The authors report a rare presentation of a ganglioneuroma of the mandible arising from a metastasis of an adrenal neuroblastoma. The pathogenesis and behaviour of ganglioneuromas is discussed, together with recommendations for their management.

The Protein Acetyltransferase ARD1: A Novel Cancer Drug Target?

Evasion of apoptosis and active cell proliferation are among the characteristics of cancer cells. Triggering the induction of apoptosis or reducing the proliferative rate will potentially be helpful for cancer treatment. Recently, several reports demonstrated that knockdown of the protein acetyltransferase hARD1 significantly reduced the growth rate of human cancer cell lines. Furthermore, hARD1 knockdown induced apoptosis or sensitized cells to drug induced apoptosis. hARD1 acts in complex with the NATH protein and catalyzes cotranslational acetylation of protein N-termini. Thus, it was suggested that the effects on cell proliferation and apoptosis induction are due to a reduced level of N-terminal acetylation of certain substrate proteins. NATH was originally identified as upregulated in thyroid papillary carcinomas and has lately also been found to correlate with aggressiveness and differentiation status of neuroblastic tumours. On the other hand, researchers recently reported that hARD1 acetylates Beta-catenin. Knockdown of hARD1 reduced the transcriptional activity of the Beta-Catenin/TCF4 complex, downregulating cyclin D1 and thereby promoting G1-arrest and inhibition of cell proliferation of lung cancer cells. Although the underlying molecular mechanisms need further clarification, several reports suggest that reduction of hARD1 negatively affects cell growth. Thus, hARD1 or the hARD1-NATH complex stands out as attractive drug targets in cancer treatment. One challenge will be to develop specific inhibitors that discriminate between hARD1 and the many other enzymes, including the histone acetyltransferases, using acetyl-coenzyme A as acetyl donor. This review focuses on the enzymatic and biological activities of hARD1, and potential mechanisms of functional inhibition.

Differential expression of genes mapping to recurrently abnormal chromosomal regions characterize neuroblastic tumours with distinct ploidy status

BackgroundNeuroblastic tumours (NBTs) represent a heterogeneous spectrum of neoplastic diseases associated with multiple genetic alterations. Structural and numerical chromosomal changes are frequent and are predictive parameters of NBTs outcome. We performed a comparative analysis of the biological entities constituted by NBTs with different ploidy status.MethodsGene expression profiling of 49 diagnostic primary NBTs with ploidy data was performed using oligonucleotide microarray. Further analyses using Quantitative Real-Time Polymerase Chain Reaction (Q-PCR); array-Comparative Genomic Hybridization (aCGH); and Fluorescent in situ Hybridization (FISH) were performed to investigate the correlation between aneuploidy, chromosomal changes and gene expression profiles.ResultsGene expression profiling of 49 primary near-triploid and near-diploid/tetraploid NBTs revealed distinct expression profiles associated with each NBT subgroup. A statistically significant portion of genes mapped to 1p36 (P = 0.01) and 17p13-q21 (P < 0.0001), described as recurrently altered in NBTs. Over 90% of these genes showed higher expression in near-triploid NBTs and the majority are involved in cell differentiation pathways. Specific chromosomal abnormalities observed in NBTs, 1p loss, 17q and whole chromosome 17 gains, were reflected in the gene expression profiles. Comparison between gene copy number and expression levels suggests that differential expression might be only partly dependent on gene copy number. Intratumoural clonal heterogeneity was observed in all NBTs, with marked interclonal variability in near-diploid/tetraploid tumours.ConclusionNBTs with different cellular DNA content display distinct transcriptional profiles with a significant portion of differentially expressed genes mapping to specific chromosomal regions known to be associated with outcome. Furthermore, our results demonstrate that these specific genetic abnormalities are highly heterogeneous in all NBTs, and suggest that NBTs with different ploidy status may result from different mechanisms of aneuploidy driving tumourigenesis.