Histopathologic prognostic factors in neuroblastic tumors: definition of subtypes of ganglioneuroblastoma and an age-linked classification of neuroblastomas

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.

Neuroblastoma: biology, prognosis, and treatment

Neuroblastoma, a neoplasm of the sympathetic nervous system, is the second most common extracranial malignant tumor of childhood and the most common solid tumor of infancy. Neuroblastoma is a heterogeneous malignancy with prognosis ranging from near uniform survival to high risk for fatal demise. Neuroblastoma serves as a paradigm for the prognostic utility of biologic and clinical data and the potential to tailor therapy for patient cohorts at low, intermediate, and high risk for recurrence. This article summarizes our understanding of neuroblastoma biology and prognostic features and discusses their impact on current and proposed risk stratification schemas, risk-based therapeutic approaches, and the development of novel therapies for patients at high risk for failure.

High-dose chemotherapy and autologous haematopoietic stem cell rescue for children with high-risk neuroblastoma

BACKGROUND

Despite the development of new treatment options, the prognosis of high-risk neuroblastoma patients is still poor; more than half of patients experience disease recurrence. High-dose chemotherapy and haematopoietic stem cell rescue (i.e. myeloablative therapy) might improve survival.

OBJECTIVES

To compare the effectiveness of myeloablative therapy with conventional therapy in children with high-risk neuroblastoma.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2009, issue 1), MEDLINE/PubMed (1966 to January 2009) and EMBASE/Ovid (1980 to January 2009). In addition, we searched reference lists of relevant articles, conference proceedings and ongoing trial databases.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing the effectiveness of myeloablative therapy with conventional therapy in high-risk neuroblastoma patients.

DATA COLLECTION AND ANALYSIS

Two authors independently performed study selection, data extraction and risk of bias assessment. If possible, we pooled results.

MAIN RESULTS

We identified three RCTs including 739 children. The meta-analysis of event-free survival showed a significant difference in favour of the myeloablative therapy group (HR 0.78; 95% CI 0.67 to 0.90), as did the meta-analysis of overall survival (HR 0.74; 95% CI 0.57 to 0.98). The meta-analysis of secondary malignant disease and treatment-related death did not show a significant difference between the treatment groups. In one study a significant difference in favour of the conventional therapy group was identified for renal effects, interstitial pneumonitis and veno-occlusive disease, whereas for serious infections and sepsis no significant difference between the treatment groups was identified. In the individual studies we evaluated different subgroups, but the results were not univocal in all studies. All studies had some methodological limitations.

AUTHORS' CONCLUSIONS

Based on the currently available evidence, myeloablative therapy seems to be a good treatment option for children with high-risk neuroblastoma. It results in higher survival rates than conventional therapy, although possible higher levels of adverse effects should be kept in mind. A definitive conclusion regarding the effect of myeloablative therapy in different subgroups is not possible. This systematic review only allows a conclusion on the concept of myeloablative therapy; no conclusions can be made regarding the best treatment strategy. Future trials on the use of myeloablative therapy for high-risk neuroblastoma should focus on identifying the most optimal induction and/or myeloablative regimen. The best study design to answer these questions is a RCT. These RCTs should be performed in homogeneous study populations (for example, regarding stage of disease and patient age) and have a long-term follow up. Different risk groups should be taken into account.

Peripheral blood stem cell support for multiple cycles of dose intensive induction therapy is feasible with little risk of tumor contamination in advanced stage neuroblastoma: a report from the Childrens Oncology Group

BACKGROUND

Poor outcome in Stage 4 neuroblastoma may be improved with increased dose intensity of therapy. We investigated the feasibility of sequential collection and infusion of peripheral blood stem cells (PBSCs) as hematopoietic support for non-myeloablative dose intensive induction chemotherapy given every 21-28 days.

METHODS

Twenty-two children with Stage 4 neuroblastoma (>or=1 year of age) received two cycles of high-dose cyclophosphamide (4 g/m(2)), doxorubicin (75 mg/m(2)), and vincristine (2 mg/m(2)) followed by three cycles of interpatient dose escalating carboplatin (Dose Level 0 = 800 mg/m(2); Dose Level 1 = 1,000 mg/m(2)), high-dose cyclophosphamide (4 g/m(2)), and etoposide (600 mg/m(2)). PBSC were harvested following cycle 2, 3, and 4 in Cohort 1 and infused after each subsequent cycle. In Cohort 2, PBSC were harvested after cycle 2 and split into three aliquots for infusion. Dose limiting toxicity (DLT) and ability to administer cycles within 28 days was assessed.

RESULTS

Sufficient PBSC (>or=2 x 10(6) CD34 cells/kg per infusion) were collected from 17/21 eligible patients with minimal toxicity and no detectable neuroblastoma cells by immunocytology. Carboplatin at 1000 mg/m(2) resulted in DLT of delayed platelet recovery >28 days in 4/8 patients. Despite de-escalation to 800 mg/m(2), platelet DLT occurred in 4/7 Cohort 1 and 3/7 Cohort 2 patients.

CONCLUSION

As defined in this protocol, doses of carboplatin were not tolerable with the PBSC dose administered. However, it was feasible to collect sufficient PBSC from small neuroblastoma patients to use as hematopoietic support with minimal risk of tumor contamination and toxicity.

Genetics and genomics of neuroblastoma

Neuroblastoma is a pediatric cancer of the developing sympathetic nervous system that most often affects young children. It remains an important pediatric problem because it accounts for approximately 15% of childhood cancer mortality. The disease is clinically heterogeneous, with the likelihood of cure varying greatly according to age at diagnosis, extent of disease, and tumor biology. This extreme clinical heterogeneity reflects the complexity of genetic and genomic events associated with development and progression of disease. Inherited genetic variants and mutations that initiate tumorigenesis have been identified in neuroblastoma and multiple somatically acquired genomic alterations have been described that are relevant to disease progression. This chapter focuses on recent genome-wide studies that have utilized high-density single nucleotide polymorphism (SNP) genotyping arrays to discover genetic factors predisposing to tumor initiation such as rare mutations at locus 2p23 (in ALK gene) for familial neuroblastoma, common SNPs at 6p22 (FLJ22536 and FLJ44180) and 2q35 (BARD1), and a copy number polymorphism at 1q21.1 (NBPF23) for sporadic neuroblastoma. It also deals with well known and recently reported somatic changes in the tumor genome such as mutations, gain of alleles and activation of oncogenes, loss of alleles, or changes in tumor-cell ploidy leading to the diverse clinical behavior of neuroblastomas. Finally, this chapter reviews gene expression profiles of neuroblastoma associated with pathways of the signaling of neurotrophins and apoptotic factors that could have a role in neuroblastoma development and progression. Looking forward, a major challenge will be to understand how inherited genetic variation and acquired somatic alterations in the tumor genome interact to exact phenotypic differences in neuroblastoma, and cancer in general.

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.

Vascular endothelial growth factor in children with neuroblastoma: a retrospective analysis

Background

Despite aggressive therapy, advanced stage neuroblastoma patients have poor survival rates. Although angiogenesis correlates with advanced tumour stage and plays an important role in determining the tumour response to treatment in general, clinical data are still insufficient, and more clinical evaluations are needed to draw conclusions. The aim of this study was to evaluate vascular endothelial growth factor (VEGF) expression in patients with neuroblastoma, determine whether it correlates with other prognostic factors and/or therapeutic response, and to assess should VEGF be considered in a routine diagnostic workup.

Materials and methods

VEGF expression was determined by immunohistochemistry using anti-VEGF antibody in paraffin embedded primary tumour tissue from 56 neuroblastoma patients. Semiquantitative expression of VEGF was estimated and compared with gender, age, histology, disease stage, therapy, and survival. Statistical analyses, including multivariate analysis, were performed.

Results

VEGF expression correlated with disease stage and survival in neuroblastoma patients. Combination of VEGF expression and disease stage as a single prognostic value for survival (P-value = 0.0034; odds ratio (OR) (95%CI) = 26.17 (2.97-230.27) exhibited greater correlation with survival than individually. Hematopoietic stem cell transplantation significantly improved survival of the advanced stage patients with high VEGF expression.

Conclusion

VEGF expression should be considered in a routine diagnostic workup of children with neuroblastoma, especially in those more than 18 months old and with advanced disease stage. High VEGF expression at the time of disease diagnosis is a bad risk prognostic factor, and can be used to characterize subsets of patients with an unfavourable outcome.

Clinicopathological characteristics of ganglioneuroma and ganglioneuroblastoma: a report from the CCG and COG

BACKGROUND

The International Neuroblastoma Pathology Classification (INPC) was the first to clearly define prognostic subgroups in ganglioneuroma (GN) and ganglioneuroblastoma (GNB).

PROCEDURE

Histopathology and tumor resectability of 552 GN/GNB cases from the Children's Cancer Group (CCG) and Children's Oncology Group (COG) neuroblastoma studies were reviewed. The results were analyzed along with clinical information and biological data of the cases.

RESULTS

According to the INPC, 300 tumors were classified into the Favorable Histology (FH) group and 252 were into the Unfavorable Histology (UH) group. Tumors in the FH group included 43 ganglioneuroma-maturing (GN-M), 198 ganglioneuroblastoma-intermixed (GNB-I), and 59 ganglioneuroblastoma-nodular, favorable subset (GNB-N-FS), and were often (91%) resected completely by single or multiple surgical procedures. Patients with the FH tumors had an excellent prognosis with no tumor-related deaths. The UH group included ganglioneuroblastoma-nodular, unfavorable subset (GNB-N-US) tumors. Patients with the UH tumors had a high incidence (53%) of distant metastasis at the time of diagnosis, and their prognosis significantly depended on clinical stage (5-year EFS: 80.1% for non-stage 4 patients; 16.7% for stage 4 patients): Complete primary tumor resection was not beneficial to those GNB-N-US patients, regardless of whether metastasis was present or not. MYCN amplification was detected in four tumors in the FH group and six tumors in the UH group. The majority (160/191, 84%) of GN-M and GNB-I tumors had a diploid pattern determined by flow cytometry.

CONCLUSIONS

Stringent application of the INPC along with clinical staging was critical for prognostic evaluation of the patients with this group of tumors.

PET/CT in the Evaluation of Neuroblastoma

I-123-metaiodobenzylguanidine (MIBG) is the most commonly used functional imaging agent in patients with neuroblastoma, but use of [F-18]- FDG PET is increasing. MIBG is useful for defining the extent of disease at diagnosis, following response to treatment, and localizing residual and recurrent disease. In early-stage disease, FDG is often better concentrated in tumor sites than MIBG. In all stages, disease extent in the chest, abdomen, and pelvis and local metastases may be better delineated by FDG. In advanced-stage disease, MIBG is superior for following the treatment response of metastatic tumor in the marrow and bone. Several C-11- and F-18-labeled tracers may be equal to or superior to I-123-MIBG if supply problems can be resolved.

Presence of cancer-associated fibroblasts inversely correlates with Schwannian stroma in neuroblastoma tumors

Stromal cells have a central function in the regulation of tumor angiogenesis. Recent studies have shown that stromal myofibroblasts (cancer-associated fibroblasts) actively promote tumor growth and enhance tumor angiogenesis in many types of adult carcinomas. To evaluate the function cancer-associated fibroblasts have in neuroblastoma angiogenesis and investigate their relationship to stromal Schwann cells, we quantified cancer-associated fibroblasts in 60 primary neuroblastoma tumors and in a novel neuroblastoma xenograft model in which murine Schwann cells were induced to infiltrate into the tumor stroma. Tumor sections were examined for presence of microvascular proliferation, a hallmark of tumor angiogenesis. Cancer-associated fibroblasts were characterized by positive immunostaining for alpha-smooth muscle actin (alpha-SMA) and were distinguished from pericytes by staining negatively for high-molecular-weight caldesmon. alpha-SMA-positive cells were quantified and their number was defined as high when >1.0% of the area was positive. Associations between high cancer-associated fibroblast number, microvascular proliferation and established prognosticators were analyzed. High numbers of cancer-associated fibroblasts were associated with Schwannian stroma-poor histopathology and microvascular proliferation. Thirty-seven (80%) of the 46 Schwannian stroma-poor tumors had high numbers of cancer-associated fibroblasts in the tumor stroma compared to only 2 (14%) of the 14 Schwannian stroma-rich/dominant tumors (P<0.001). Thirty-three (89%) of 37 tumors with microvascular proliferation had high numbers of cancer-associated fibroblasts compared to 9 (40%) of 22 tumors without microvascular proliferation (P<0.001). In the xenografts with infiltrating Schwann cells (n=10), the number of cancer-associated fibroblasts per mm(2) was approximately sevenfold less than in the control xenografts without stromal Schwann cells (n=9) (mean of 51+/-30 vs 368+/-105, respectively; P<0.001). Thus, cancer-associated fibroblasts were inversely associated with presence of Schwann cells, suggesting that Schwann cells may prevent the activation of fibroblasts. A deeper understanding of the function cancer-associated fibroblasts have in neuroblastoma angiogenesis may guide future development of stroma-directed therapeutic strategies.

Neuroblastoma originating from extra-abdominal sites: association with favorable clinical and biological features

Neuroblastomas originating from different sites might have different clinical and biological characteristics. In the present study, the clinical (age, sex and stage) and biological (N-myc amplification, Shimada pathology and levels of lactate dehydrogenase, ferritin and neuron-specific enolase) characteristics of patients with newly diagnosed neuroblastoma were compared according to the site of tumor origin (extra-abdominal versus abdominal). The event-free survival rate (EFS) was also compared between the two groups. Among 143 neuroblastomas, 115 tumors originated from the abdomen, 26 from extra-abdominal sites and 2 from unknown primary sites. Frequencies of stage 4 tumor and N-myc amplified tumor were lower in the extra-abdominal group than in the abdominal group (34.6% vs. 60.0%, P=0.019 and 4.2% vs. 45.0%, P<0.001, respectively). Levels of lactate dehydrogenase, ferritin and neuron-specific enolase were significantly lower in the extra-abdominal group than in the abdominal group. The probability of 5-yr EFS (+/-95% confidence interval) was higher in the extra-abdominal group than in the abdominal group (94.4+/-10.6% vs. 69.4+/-9.4%, P=0.026). Taken together, neuroblastomas originating from extra-abdominal sites might be associated with more favorable clinical and biological characteristics and a better outcome than neuroblastomas originating from abdomen.

Comparison of primary neuroblastoma tumors and derivative early-passage cell lines using genome-wide single nucleotide polymorphism array analysis

Stromal contamination is one of the major confounding factors in the analysis of solid tumor samples by single nucleotide polymorphism (SNP) arrays. As we propose to use genome-wide SNP microarray analysis as a diagnostic platform for neuroblastoma, the sensitivity, specificity, and accuracy of these studies must be optimized. To investigate the effects of stromal contamination, we derived early-passage cell lines from nine primary tumors and compared their genomic signature with that of the primary tumors using 100K SNP arrays. The average concordance between tumor and cell line for raw loss of heterozygosity (LOH) calls was 96% (range, 91-99%) and for raw copy number alterations, 71% (range, 43-87%). In general, there were a larger number of LOH events identified in the cell lines compared with the matched tumor samples (mean increase, 3.2% +/- 1.9%). We have developed an algorithm that shows that the presence of stroma contributes to under-reporting of LOH and copy number loss. Notable findings in this sample set were uniparental disomy of chromosome arms 11p, 1q, 14q, and 15q and a novel area of amplification on chromosome band 11p15. Our analysis shows that LOH was identified significantly more often in derived cell lines compared with the original tumor samples. Although these may in part be due to clonal selection during adaptation to tissue culture, our study indicates that stromal contamination may be a major contributing factor in underestimation of LOH and copy number loss events.

Histone deacetylase 8 in neuroblastoma tumorigenesis

PURPOSE

The effects of pan-histone deacetylase (HDAC) inhibitors on cancer cells have shown that HDACs are involved in fundamental tumor biological processes such as cell cycle control, differentiation, and apoptosis. However, because of the unselective nature of these compounds, little is known about the contribution of individual HDAC family members to tumorigenesis and progression. The purpose of this study was to evaluate the role of individual HDACs in neuroblastoma tumorigenesis.

EXPERIMENTAL DESIGN

We have investigated the mRNA expression of all HDAC1-11 family members in a large cohort of primary neuroblastoma samples covering the full spectrum of the disease. HDACs associated with disease stage and survival were subsequently functionally evaluated in cell culture models.

RESULTS

Only HDAC8 expression was significantly correlated with advanced disease and metastasis and down-regulated in stage 4S neuroblastoma associated with spontaneous regression. High HDAC8 expression was associated with poor prognostic markers and poor overall and event-free survival. The knockdown of HDAC8 resulted in the inhibition of proliferation, reduced clonogenic growth, cell cycle arrest, and differentiation in cultured neuroblastoma cells. The treatment of neuroblastoma cell lines as well as short-term-culture neuroblastoma cells with an HDAC8-selective small-molecule inhibitor inhibited cell proliferation and clone formation, induced differentiation, and thus reproduced the HDAC8 knockdown phenotype. Global histone 4 acetylation was not affected by HDAC8 knockdown or by selective inhibitor treatment.

CONCLUSIONS

Our data point toward an important role of HDAC8 in neuroblastoma pathogenesis and identify this HDAC family member as a specific drug target for the differentiation therapy of neuroblastoma.

Neuroblastoma cell lines contain pluripotent tumor initiating cells that are susceptible to a targeted oncolytic virus

Background

Although disease remission can frequently be achieved for patients with neuroblastoma, relapse is common. The cancer stem cell theory suggests that rare tumorigenic cells, resistant to conventional therapy, are responsible for relapse. If true for neuroblastoma, improved cure rates may only be achieved via identification and therapeutic targeting of the neuroblastoma tumor initiating cell. Based on cues from normal stem cells, evidence for tumor populating progenitor cells has been found in a variety of cancers.

Methodology/Principal Findings

Four of eight human neuroblastoma cell lines formed tumorspheres in neural stem cell media, and all contained some cells that expressed neurogenic stem cell markers including CD133, ABCG2, and nestin. Three lines tested could be induced into multi-lineage differentiation. LA-N-5 spheres were further studied and showed a verapamil-sensitive side population, relative resistance to doxorubicin, and CD133+ cells showed increased sphere formation and tumorigenicity. Oncolytic viruses, engineered to be clinically safe by genetic mutation, are emerging as next generation anticancer therapeutics. Because oncolytic viruses circumvent typical drug-resistance mechanisms, they may represent an effective therapy for chemotherapy-resistant tumor initiating cells. A Nestin-targeted oncolytic herpes simplex virus efficiently replicated within and killed neuroblastoma tumor initiating cells preventing their ability to form tumors in athymic nude mice.

Conclusions/Significance

These results suggest that human neuroblastoma contains tumor initiating cells that may be effectively targeted by an oncolytic virus.

Genomic copy number determination in cancer cells from single nucleotide polymorphism microarrays based on quantitative genotyping corrected for aneuploidy

Microarrays are frequently used to profile genome-wide copy number (CN) aberrations. While generally robust for detecting CN variants in germline DNA, the methods used to derive CN from signal intensity values have been suboptimal when applied to cancer genomes. The complexity of genomic aberrations in cancer makes it more difficult to discriminate between signal and noise, and measuring CN as a discrete variable does not account for tumor heterogeneity. Furthermore, standard normalization approaches detect CN changes relative to the overall DNA content, which is often not diploid in cancer. We propose an algorithm that uses the degree of allelic imbalance as well as probe intensity, with a correction for aneuploidy, for a quantitative CN assessment and scoring of allelic ratios. This algorithm results in a more precise definition of CN and allelic aberration in the cancer genome, which is essential for translational efforts focused on using these tools for molecular diagnostics and for the discovery of therapeutic targets.

Anaplastic large cell neuroblastoma

Anaplastic large cell neuroblastomas (ALCNB) are a subset of undifferentiated neuroblastomas with marked pleomorphic and anaplastic features that render them diagnostically challenging. We reviewed the records of all patients diagnosed with ALCNB at Children's Healthcare of Atlanta (Egleston Children's Hospital) for their clinical, biologic, and pathologic characteristics and their treatment outcomes. From 1998 to 2006, 7 patients were diagnosed with ALCNB. All patients presented with abdominal-pelvic masses, 3 of them of adrenal origin and 2 with thoracic extension, with clinical stages 3 or 4, and were considered to have high-risk disease. The N-MYC oncogene was amplified in 3 cases and catecholamines were elevated in 5 of 6 patients tested. All pretreatment tumors demonstrate pleomorphic, anaplastic morphology with bizarre mitoses admixed with undifferentiated but monomorphic cells with minimal if any neuropil or neuro-ganglionic differentiation. Immunohistochemical markers for neuron specific enolase (NSE) and synaptophysin were strongly positive in all specimens and chromogranin in 4 of 5. Interestingly, all tumors showed strong Fli-1 nuclear positivity despite a negative CD-99 stain. However, reverse transcription polymerase chain reaction or fluorescent in-situ hybridization testing for Ewing sarcoma transcripts was negative in 4 available specimens. This same Fli-1 antibody had tested negative on 30 conventional neuroblastomas, indicating a peculiar cross reactivity with this subset of ALCNB. Posttreatment biopsies showed maturation changes to more conventional neuroblastoma histology in 5 of the 7 cases. Follow-up ranged from 9 months to 4 years from diagnosis (median: 25 months). Five patients are still alive after treatment, 1 died 9 months after diagnosis, and another patient refused high-risk therapy and progressed and died 9 months from diagnosis. Anaplastic large cell neuroblastomas are a subset of undifferentiated neuroblastomas characterized by the absence or marked paucity of histologic clues for the diagnosis of neuroblastoma. Although all these tumors are strongly positive for NSE and synaptophysin, they also show Fli-1 positivity. However, they are negative by molecular testing for EWS transcripts, and they are immunohistochemically negative for CD99. The true neuroblastic nature of these tumors is supported by the N-MYC oncogene amplification in some of them, catecholamine production, immunohistological reactivity, and their posttherapy maturation to a more recognizable neuroblastic morphology. Although follow-up is still somewhat limited, the response and survival of the patients in our institution is better than a previous European study that indicated an aggressive clinical behavior of these tumors, although treatment modalities were not described in that report. Further study of this variant of neuroblastoma with more patients is required to determine optimal therapy, more accurately predict outcome, and to ascertain if ALCNB are a distinct biologic group of neuroblastomas.

Outcome of high-risk stage 3 neuroblastoma with myeloablative therapy and 13-cis-retinoic acid: a report from the Children's Oncology Group

BACKGROUND

The components of therapy required for patients with INSS Stage 3 neuroblastoma and high-risk features remain controversial.

PROCEDURE

A retrospective cohort design was used to determine if intensive chemoradiotherapy with purged autologous bone marrow rescue (ABMT) and/or 13-cis-retinoic acid (13-cis-RA) improved outcome for patients with high-risk neuroblastoma that was not metastatic to distant sites. We identified 72 patients with INSS Stage 3 neuroblastoma enrolled between 1991 and 1996 on the Phase 3 CCG-3891 randomized trial. Patients were analyzed on an intent-to-treat basis using a log-rank test.

RESULTS

The 5-year event-free survival (EFS) and overall survival (OS) rates for patients with Stage 3 neuroblastoma were 55 +/- 6% and 59 +/- 6%, respectively (n = 72). Patients randomized to ABMT (n = 20) had 5-year EFS of 65 +/- 11% and OS of 65 +/- 11% compared to 41 +/- 11 (P = 0.21) and 46 +/- 11% (P = 0.23) for patients randomized to CC (n = 23), respectively. Patients randomized to 13-cis-RA (n = 23) had 5-year EFS of 70 +/- 10% and OS of 78 +/- 9% compared to 63 +/- 12% (P = 0.67) and 67 +/- 12% (P = 0.55) for those receiving no further therapy (n = 16), respectively. Patients randomized to both ABMT and 13-cis-RA (n = 6) had a 5-year EFS of 80 +/- 11% and OS of 100%.

CONCLUSION

Patients with high-risk Stage 3 neuroblastoma have an overall poor prognosis despite aggressive chemoradiotherapy. Further studies are warranted to determine if myeloablative consolidation followed by 13-cis-RA maintenance therapy statistically significantly improves outcome.

Significance of MYCN amplification in international neuroblastoma staging system stage 1 and 2 neuroblastoma: a report from the International Neuroblastoma Risk Group database

PURPOSE

Treatment of patients with localized neuroblastoma with unfavorable biologic features is controversial. To evaluate the outcome of children with low-stage MYCN-amplified neuroblastoma and develop a rational treatment strategy, data from the International Neuroblastoma Risk Group (INRG) database were analyzed.

PATIENTS AND METHODS

The database is comprised of 8,800 patients. Of these, 2,660 patients (30%) had low-stage (International Neuroblastoma Staging System stages 1 and 2) neuroblastoma, known MYCN status, and available follow-up data. Eighty-seven of these patients (3%) had MYCN amplified tumors.

RESULTS

Patients with MYCN-amplified, low-stage tumors had less favorable event-free survival (EFS) and overall survival (OS) than did patients with nonamplified tumors (53% +/- 8% and 72% +/- 7% v 90% +/- 1% and 98% +/- 1%, respectively). EFS and OS were statistically significantly higher for patients whose tumors were hyperdiploid rather than diploid (EFS, 82% +/- 20% v 37% +/- 21%; P = .0069; OS, 94% +/- 11% v 54% +/- 15%; P = .0056, respectively). No other variable had prognostic significance. Initial treatment consisted of surgery alone for 29 (33%) of 87 patients. Details of additional therapy were unknown for 14 patients. Twenty-two patients (25%) underwent surgery and moderate-intensity chemotherapy; another 22 underwent surgery, intensive chemotherapy, and radiation therapy. Nine of the latter 22 underwent stem cell transplantation. Survival in patients who received transplantation did not differ from survival in those who did not receive transplantation.

CONCLUSION

Among patients with low-stage, MYCN-amplified neuroblastoma, outcomes of patients with hyperdiploid tumors were statistically, significantly better than those with diploid tumors. The data suggest that tumor cell ploidy could potentially be used to identify candidates for reductions in therapy. Further study of MYCN-amplified, low-stage neuroblastoma is warranted.

The International Neuroblastoma Risk Group (INRG) classification system: an INRG Task Force report

PURPOSE

Because current approaches to risk classification and treatment stratification for children with neuroblastoma (NB) vary greatly throughout the world, it is difficult to directly compare risk-based clinical trials. The International Neuroblastoma Risk Group (INRG) classification system was developed to establish a consensus approach for pretreatment risk stratification.

PATIENTS AND METHODS

The statistical and clinical significance of 13 potential prognostic factors were analyzed in a cohort of 8,800 children diagnosed with NB between 1990 and 2002 from North America and Australia (Children's Oncology Group), Europe (International Society of Pediatric Oncology Europe Neuroblastoma Group and German Pediatric Oncology and Hematology Group), and Japan. Survival tree regression analyses using event-free survival (EFS) as the primary end point were performed to test the prognostic significance of the 13 factors.

RESULTS

Stage, age, histologic category, grade of tumor differentiation, the status of the MYCN oncogene, chromosome 11q status, and DNA ploidy were the most highly statistically significant and clinically relevant factors. A new staging system (INRG Staging System) based on clinical criteria and tumor imaging was developed for the INRG Classification System. The optimal age cutoff was determined to be between 15 and 19 months, and 18 months was selected for the classification system. Sixteen pretreatment groups were defined on the basis of clinical criteria and statistically significantly different EFS of the cohort stratified by the INRG criteria. Patients with 5-year EFS more than 85%, more than 75% to < or = 85%, > or = 50% to < or = 75%, or less than 50% were classified as very low risk, low risk, intermediate risk, or high risk, respectively.

CONCLUSION

By defining homogenous pretreatment patient cohorts, the INRG classification system will greatly facilitate the comparison of risk-based clinical trials conducted in different regions of the world and the development of international collaborative studies.

Lung metastases in neuroblastoma at initial diagnosis: A report from the International Neuroblastoma Risk Group (INRG) project

BACKGROUND

Neuroblastoma is the most common extracranial pediatric solid cancer. Lung metastasis is rarely detected in children with newly diagnosed neuroblastoma. We aimed to describe the incidence, clinical characteristics, and outcome of patients with lung metastasis at initial diagnosis using a large international database.

PROCEDURE

The subset of patients from the International Neuroblastoma Risk Group database with INSS stage 4 neuroblastoma and known data regarding lung metastasis at diagnosis was selected for analysis. Clinical and biological characteristics were compared between patients with and without lung metastasis. Survival for patients with and without lung metastasis was estimated by Kaplan-Meier methods. Cox proportional hazards methods were used to determine the independent prognostic value of lung metastasis at diagnosis.

RESULTS

Of the 2,808 patients with INSS stage 4 neuroblastoma diagnosed between 1990 and 2002, 100 patients (3.6%) were reported to have lung metastasis at diagnosis. Lung metastasis was more common among patients with MYCN amplified tumors, adrenal primary tumors, or elevated lactate dehydrogenase (LDH) levels (P < 0.02 in each case). Five-year overall survival +/- standard error for patients with lung metastasis was 34.5% +/- 6.8% compared to 44.7% +/- 1.3% for patients without lung metastasis (P = 0.0002). However, in multivariable analysis, the presence of lung metastasis was not independently predictive of outcome.

CONCLUSIONS

Lung metastasis at initial diagnosis of neuroblastoma is associated with MYCN amplification and elevated LDH levels. Although lung metastasis at diagnosis was not independently predictive of outcome in this analysis, it remains a useful prognostic marker of unfavorable outcome.

Simultaneous occurrence of right adrenocortical tumor and left adrenal neuroblastoma in an infant with Beckwith-Wiedemann syndrome

Children with Beckwith-Wiedemann syndrome (BWS) have increased risk for development of embryonal tumors. We present the case of an infant with BWS who has hypomethylation of LIT1 gene in the 11p15.5 chromosomal region and at 6 months of age presented with simultaneous occurrence of neuroblastoma arising from the left adrenal gland and a right adrenocortical tumor. She underwent surgical resection of both tumors and remains tumor free 18 months after surgery.

SPARC in cancer biology: its role in cancer progression and potential for therapy

The ability to effectively target a tumor to achieve complete regression and cure is the ultimate goal that drives our need to better understand tumor biology. Recently, SPARC has generated considerable interest as a multi-faceted protein that belongs to a family of matricellular proteins. It functions not only to modulate cell-cell and cell-matrix interactions, but its de-adhesive and growth inhibitory properties in non-transformed cells have led to studies to assess its role in cancer. Its divergent actions reflect the complexity of this protein, because in certain types of cancers, such as melanomas and gliomas, SPARC is associated with a highly aggressive tumor phenotype, while in others, mainly ovarian, neuroblastomas and colorectal cancers, SPARC may function as a tumor suppressor. Recent studies have also demonstrated a role for SPARC in sensitizing therapy-resistant cancers. Here, the role of SPARC in cancer progression and its potential application in cancer therapy is discussed.

High Myc pathway activity and low stage of neuronal differentiation associate with poor outcome in neuroblastoma

The childhood cancer neuroblastoma arises in the developing sympathetic nervous system and is a genotypically and phenotypically heterogeneous disease. Prognostic markers of poor survival probability include amplification of the MYCN oncogene and an undifferentiated morphology. Whereas these features discriminate high- from low-risk patients with precision, identification of poor outcome low- and intermediate-risk patients is more challenging. In this study, we analyze two large neuroblastoma microarray datasets using a priori-defined gene expression signatures. We show that differential overexpression of Myc transcriptional targets and low expression of genes involved in sympathetic neuronal differentiation predicts relapse and death from disease. This was evident not only for high-risk patients but was also robust in identifying groups of poor prognosis patients who were otherwise judged to be at low- or intermediate-risk for adverse outcome. These data suggest that pathway-specific gene expression profiling might be useful in the clinic to adjust treatment strategies for children with neuroblastoma.

Radiolabeled metaiodobenzylguanidine for the treatment of neuroblastoma

INTRODUCTION

Neuroblastoma is the most common pediatric extracranial solid cancer. This tumor is characterized by metaiodobenzylguanidine (MIBG) avidity in 90% of cases, prompting the use of radiolabeled MIBG for targeted radiotherapy in these tumors.

METHODS

The available English language literature was reviewed for original research investigating in vitro, in vivo and clinical applications of radiolabeled MIBG for neuroblastoma.

RESULTS

MIBG is actively transported into neuroblastoma cells by the norepinephrine transporter. Preclinical studies demonstrate substantial activity of radiolabeled MIBG in neuroblastoma models, with (131)I-MIBG showing enhanced activity in larger tumors compared to (125)I-MIBG. Clinical studies of (131)I-MIBG in patients with relapsed or refractory neuroblastoma have identified myelosuppression as the main dose-limiting toxicity, necessitating stem cell reinfusion at higher doses. Most studies report a response rate of 30-40% with (131)I-MIBG in this population. More recent studies have focused on the use of (131)I-MIBG in combination with chemotherapy or myeloablative regimens.

CONCLUSIONS

(131)I-MIBG is an active agent for the treatment of patients with neuroblastoma. Future studies will need to define the optimal role of this targeted radiopharmaceutical in the therapy of this disease.

The kinesin KIF1Bbeta acts downstream from EglN3 to induce apoptosis and is a potential 1p36 tumor suppressor

VHL, NF-1, c-Ret, and Succinate Dehydrogenase Subunits B and D act on a developmental apoptotic pathway that is activated when nerve growth factor (NGF) becomes limiting for neuronal progenitor cells and requires the EglN3 prolyl hydroxylase as a downstream effector. Germline mutations of these genes cause familial pheochromocytoma and other neural crest-derived tumors. Using an unbiased shRNA screen we found that the kinesin KIF1Bbeta acts downstream from EglN3 and is both necessary and sufficient for neuronal apoptosis when NGF becomes limiting. KIF1Bbeta maps to chromosome 1p36.2, which is frequently deleted in neural crest-derived tumors including neuroblastomas. We identified inherited loss-of-function KIF1Bbeta missense mutations in neuroblastomas and pheochromocytomas and an acquired loss-of-function mutation in a medulloblastoma, arguing that KIF1Bbeta is a pathogenic target of these deletions.

Clinical significance of MYCN amplification and ploidy in favorable-stage neuroblastoma: a report from the Children's Oncology Group

PURPOSE

MYCN amplification is rarely detected in patients with favorable-stage neuroblastoma (NB). To determine the clinical significance of MYCN amplification in children with favorable-stage NB, we performed a retrospective review of data from the Pediatric Oncology Group (POG) biology study 9047.

PATIENTS AND METHODS

MYCN status, tumor cell ploidy, treatment, and outcome of patients with stage A, B, or Ds NB, enrolled on POG 9047 between 1990 and 1999 were analyzed. Event-free survival (EFS) and overall (OS) survival rates were analyzed using the Kaplan-Meier method.

RESULTS

Of the 1,667 patients enrolled on POG 9047, 643 had favorable-stage disease. Of these, follow-up data were available on 568 (34%) with stage A, B, or Ds disease and normal MYCN copy number, and 32 (1.9%) patients with MYCN-amplified, stage A, B, or Ds tumors. Within the cohort lacking MYCN amplification, the 7-year EFS and OS rates (+/- SE) were 91% +/- 1% and 96% +/- 1%, respectively. Patients with MYCN amplification had significantly worse EFS and OS (50% +/- 9% and 59% +/- 9%, respectively, P < .0001). Within the cohort of children with MYCN amplification, the 7-year EFS and OS rates were 80% +/- 10% and 87% +/- 9%, respectively for patients with hyperdiploid tumors and 25% +/- 11% and 38% +/- 12% for patients with diploid/hypodiploid NBs (P = .0063 and P = .0074, respectively).

CONCLUSION

Tumor cell ploidy may be a clinically useful factor for prognostication and treatment stratification in children with MYCN-amplified, favorable-stage NB tumors.

Neuroblastoma: biology, prognosis, and treatment

Neuroblastoma, a neoplasm of the sympathetic nervous system, is the second most common extracranial malignant tumor of childhood and the most common solid tumor of infancy. Neuroblastoma is a heterogeneous malignancy with prognosis ranging from near uniform survival to high risk for fatal demise. Neuroblastoma serves as a paradigm for the prognostic utility of biologic and clinical data and the potential to tailor therapy for patient cohorts at low, intermediate, and high risk for recurrence. This article summarizes our understanding of neuroblastoma biology and prognostic features and discusses their impact on current and proposed risk stratification schemas, risk-based therapeutic approaches, and the development of novel therapies for patients at high risk for failure.

Expression and clinical significance of stem cell marker CD133 in human neuroblastoma

BACKGROUND

Recent evidences indicate that CD133, a kind of transmembrane protein, can be used as a marker to isolate stem cells from tumors originating from neural crest. This study was undertaken to explore the expression and clinical significance of stem cell marker CD133 in neuroblastoma (NB).

METHODS

Immunohistochemical staining was used to detect the expression of CD133 in 32 patients with NB and 8 patients with ganglioneuroblastoma (GNB). The relationships were analyzed among CD133 expression, international neuroblastoma staging system (INSS) stages, pathological classification, and postoperative survival time of NB patients.

RESULTS

The expression rates of CD133 in NB and GNB were 46.9% (15/32) and 37.5% (3/8) respectively, mainly in cytoplasm of neuroblastoma cells. The expression rates of stage 1-2, stage 3-4 and stage 4S were 30.7%, 57.9% and 37.5%, respectively. The differences in various stages were significant (P<0.05). The positive rate of CD133 in patients with unfavorable histology (52.4%) was significantly higher than that in patients with favorable histology (36.8%) (P=0.007). The survival time of CD133 negative patients was significantly longer than that of CD133 positive patients (P=0.026).

CONCLUSIONS

CD133 which might be correlated with the development and progression of NB can serve as one of the important indicators for prognosis of NB.

Expression of prenylated Rab acceptor 1 domain family, member 2 (PRAF2) in neuroblastoma: correlation with clinical features, cellular localization, and cerulenin-mediated apoptosis regulation

PURPOSE

Prenylated Rab acceptor 1 domain family, member 2 (PRAF2) is a novel 19-kDa protein that has recently been implicated in human cancer. In the present study, we analyzed for the first time PRAF2 mRNA expression in a large set of human tumors. The high expression in neuroblastic tumors prompted us to analyze PRAF2 expression correlations with genetic and clinical features of these tumors. In addition, we determined the localization of PRAF2 protein in neuroblastoma cells and studied its regulation in apoptosis.

EXPERIMENTAL DESIGN

Affymetrix microarray analysis was done with a set of 41 different tumor types (1,426 samples) in the public domain, a set of three different neuroblastic tumor types (110 samples), and a panel of 25 neuroblastoma cell lines. The subcellular localization of endogenous PRAF2 in neuroblastoma cells was identified by immunofluorescence microscopy and apoptosis detected by Annexin V staining and poly(ADP-ribose) polymerase cleavage.

RESULTS

PRAF2 mRNA was detected in 970 of 1,426 samples in the public data set. All 110 neuroblastic tumors expressed PRAF2 at higher levels than any other tumor examined. Importantly, PRAF2 expression levels significantly correlated with the following clinical features: patient age at diagnosis (P = 6.19 x 10(-5)), survival (P = 1.32 x 10(-3)), International Neuroblastoma Staging System stage (P = 2.86 x 10(-4)), and MYCN amplification (P = 3.74 x 10(-3)). PRAF2 localized in bright cytoplasmic punctae and protein levels increased in neuroblastoma cells that underwent cerulenin-induced apoptosis.

CONCLUSIONS

Elevated PRAF2 expression levels correlated with unfavorable genetic and clinical features, suggesting PRAF2 as a candidate prognostic marker of neuroblastoma.

Molecular biology of neuroblastoma

Neuroblastoma is one of the most frequently occurring solid tumours in children, especially in the first year of life, when it accounts for 50% of all tumours. It is the second most common cause of death in children, only preceded by accidents. The most peculiar characteristic of neuroblastoma is its clinical heterogeneity. Approximately half of the cases are classified as high risk, with overall survival rates around 40% despite intensive multimodal therapy. Nevertheless, other subsets of neuroblastomas will undergo spontaneous regression and others will show very slow progression. Despite many advances in the past three decades, neuroblastoma has remained an enigmatic challenge to clinical and basic scientists. Elucidation of the exact molecular pathways of neuroblastoma will enable researchers and clinicians to stratify the disease and adapt therapy to the risk of relapse or progression. This review focuses on recent advances in our understanding of the biology of this complex paediatric tumour. Neuroblastoma is already one of the first examples for the use of tumoral genetic markers as a tool for defining tumour behaviour and to aid clinical staging.

Pathology of peripheral neuroblastic tumors: significance of prominent nucleoli in undifferentiated/poorly differentiated neuroblastoma

The presence of large cells having simultaneously increased cytoplasmic and nuclear volume accompanied by prominent nucleoli; i.e., differentiating neuroblasts and ganglion cells, is well documented in peripheral neuroblastic tumors (pNTs), and considered as one of the signs of tumor maturation and an indication of a better prognosis of the patients. On the other hand, in 2004 it was reported that large-cell neuroblastoma composed of neuroblastic cells with only nuclear enlargement without recognizable cytoplasmic maturation behaved poorly clinically. Here we are proposing a new pNT subtype in the neuroblastoma category, in addition to the undifferentiated, poorly differentiated and differentiating subtypes: that is large nucleolar neuroblastoma (LNN) characterized by large prominent nucleoli and no or very little amount of discernible cytoplasm. LNN, whose neuroblastic cells are often large in size due to nuclear enlargement, includes those tumors previously categorized into the large-cell neuroblastoma group. LNN tumors, regardless of the size of nuclei, seem to behave aggressively with a very poor prognosis of the patients. It is speculated that nucleolar enlargement without cytoplasmic maturation in LNN tumor cells can be a sign of MYCN amplification.

Intraoperative radiation therapy for advanced neuroblastoma: the problem of securing the IORT field

The purpose of this study is to evaluate the efficacy of intraoperative radiation therapy (IORT) and the problem of securing the IORT field in advanced pediatric neuroblastoma. Between 1996 and 2005, 12 children received IORT for advanced pediatric neuroblastoma patients. Electron beam energies ranged from 10 to 12 MeV and median dose was 10 Gy (8-12 Gy). All of them had surgery with IORT against the primary tumor site and the abdominal aorta surroundings. A gross total resection (GTR) was achieved in 10 patients and subtotal resection (STR) was two patients. All of 12 patients were classified as high risk. Nine patients were alive 17-120 (mean 48 months) after diagnosis. Local tumor control was achieved in 100% of patients, of whom one experienced local recurrence outside the IORT field. At the operation, it was difficult to secure the IORT field because of the angle of the radiation cylinder in three patients. One of the three of these patients experienced local recurrence outside of the IORT field in the upper side of superior mesenteric artery and two of three patients had an external beam radiation after surgery, and there was no local recurrence. One patient had a postoperative ileus, and one patient had transient diarrhea and hydronephrosis. For advanced neuroblastoma patients, IORT produced excellent local control after surgery. However, there is a problem of securing the IORT field. For local control, it is necessary to add an external beam radiation after IORT when it is difficult to secure the IORT field.

Classification of neuroblastomas based on an analysis of the expression of genes related to prognosis

PURPOSE

To select the optimal treatment according to the grade of malignancy of neuroblastoma (NB), it is essential to accurately and rapidly identify genetic abnormalities associated with the prognosis. We have identified BIN1 and neuronatin beta as the novel prognosis-related genes for NBs. This study aims to assess the correlation between the combination of the expression level of prognosis-related genes and the outcome of NB.

METHODS

In 44 NB samples, the expression levels of TrkA, BIN1, and neuronatin beta were determined using quantitative reverse transcriptase-polymerase chain reaction; furthermore, the correlation between the expression of these genes' expression levels and the clinical progression of NB were assessed.

RESULTS

It was possible to classify 44 NBs into 4 groups regarding the grade of malignancy of NB. These 4 groups were all significantly associated with the clinical stages international NB staging system as well as the outcomes of the patients (P < .001, according to the trend test by Kruskal-Wallis exact test).

CONCLUSION

The combination of the expression levels of these genes using quantitative reverse transcriptase-polymerase chain reaction is indicated as the effective method to quickly and accurately evaluate the grade of malignancy of NBs.

Immunohistochemical expressions of Cap43 and Mina53 proteins in neuroblastoma

BACKGROUND

We studied the expressions of both Mina53, which is a myc target gene and is related to cell proliferation, and Cap43, which is related to metastasis suppression and downregulation of MYCN gene, in neuroblastoma.

METHODS

Forty-eight surgically obtained neuroblastoma specimens were immunohistochemically stained. The Cap43 and Mina53 expression levels were determined, and their relationship to clinical prognostic factors, biological prognostic factors, and the patients' prognosis were examined.

RESULTS

The Cap43 expression score was significantly high in the cases that had one of the good prognostic factors (<1 year old, early stage, mass screening case, no MYCN gene amplification), whereas the Mina53 expression score was high in those with poor prognostic factors. Regarding the MYCN expression site, the Cap43 expression score was significantly high in the cases demonstrating cytoplasm expression, whereas the Mina53 expression score was significantly high in the cases demonstrating nucleus expression. A significant relationship was found between Cap43 and TrkA, between Mina53 and Ki-67, and between Mina53 and TrkA. The prognosis was significantly favorable in the Cap43 high-expression cases, whereas it was significantly poor in the Mina53 high-expression cases.

CONCLUSIONS

Cap43 and Mina53 are both considered to be important biological and prognostic factors in neuroblastoma.

Malignant progression and blockade of angiogenesis in a murine transgenic model of neuroblastoma

Targeted expression of MYCN to the neural crest [under control of the rat tyrosine hydroxylase (TH) promoter] causes neuroblastoma in transgenic mice (TH-MYCN) and is a well-established model for this disease. Because high levels of MYCN are associated with enhanced tumor angiogenesis and poor clinical outcome in neuroblastoma, we serially characterized malignant progression, angiogenesis, and sensitivity to angiogenic blockade in tumors from these animals. Tumor cells were proliferative, secreted high levels of the angiogenic ligand vascular endothelial growth factor (VEGF), and recruited a complex vasculature expressing the angiogenic markers VEGF-R2, alpha-SMA, and matrix metalloproteinases MMP-2 and MMP-9, all of which are also expressed in human disease. Treatment of established murine tumors with the angiogenesis inhibitor TNP-470 caused near-complete ablation, with reduced proliferation, enhanced apoptosis, and vasculature disruption. Because TNP-470 has been associated with neurotoxicity, we tested the recently described water-soluble HPMA copolymer-TNP-470 conjugate (caplostatin), which showed comparable efficacy and was well tolerated without weight loss or neurotoxicity as measured by rotarod testing. This study highlights the importance of angiogenesis inhibition in a spontaneous murine tumor with native tumor-microenvironment interactions, validates the use of mice transgenic for TH-MYCN as a model for therapy in this common pediatric tumor, and supports further clinical development of caplostatin as an antiangiogenic therapy in childhood neuroblastoma.

Fetal and neonatal neuroblastoma: retrospective review of 271 cases

Neuroblastoma is the foremost malignant neoplasm of the fetus and neonate. The tumor is unique because of its distinctive biologic behavior and many different clinical manifestations. The purpose of this review is to focus on the fetus and neonate to determine the various ways perinatal neuroblastomas differ clinically and morphologically and in their treatment from those found in the older child to show that some forms of the tumor have a better outcome than others. The report attempts to evaluate the influence of site, histology, stage, biologic markers, and treatment on survival.

Neuroblastoma

The clinical hallmark of neuroblastoma is heterogeneity, with the likelihood of cure varying widely according to age at diagnosis, extent of disease, and tumour biology. A subset of tumours will undergo spontaneous regression while others show relentless progression. Around half of all cases are currently classified as high-risk for disease relapse, with overall survival rates less than 40% despite intensive multimodal therapy. This Seminar focuses on recent advances in our understanding of the biology of this complex paediatric solid tumour. We outline plans for the development of a uniform International Neuroblastoma Risk Group (INRG) classification system, and summarise strategies for risk-based therapies. We also update readers on new discoveries related to the underlying molecular pathogenesis of this tumour, with special emphasis on advances that are translatable to the clinic. Finally, we discuss new approaches to treatment, including recently discovered molecular targets that might provide more effective treatment strategies with the potential for less toxicity.

Genome-wide analysis of neuroblastomas using high-density single nucleotide polymorphism arrays

Background

Neuroblastomas 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.

Findings

Multiple 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.

Conclusions

This 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.

Correlation of modified Shimada classification with MYCN and 1p36 status detected by fluorescence in situ hybridization in neuroblastoma

Neuroblastoma (NB) is a childhood cancer derived from neural crest cells, with a highly variable clinical course and biologic behavior. NB cells harbor complex genetic changes. Also, MYCN amplification is a well-known molecular marker for aggressive progression, and deletion of the short arm of chromosome 1 is frequently observed in NB. The aim of this study was to investigate the correlation between genetic markers and prognostic morphological parameters to address the biology and underlying the clinical complexity of NB. Therefore, we performed fluorescence in situ hybridization analyses of chromosome band 1p36 and MYCN in a series of tumors from 43 cases classified according to the recommendation of International Neuroblastoma Pathology Committee (modification of Shimada classification). The correlations of MYCN amplification status and two distinct types of 1p36 alterations (deletion and imbalance) with Shimada classification and histologic prognostic factors were statistically analyzed. Amplification of MYCN and 1p36 deletion was present in 14 (32.6%) and 18 (41.9%) cases, respectively. Sixteen cases (37.2%) displayed a favorable histology, while 27 (62.8%) had an unfavorable histology. The 1p36 deletion was found to be an independent predictor of unfavorable histology by multivariate analysis (logistic regression test, P = 0.03), but the 1p36 imbalance did not show any significance. Both 1p36 deletion and MYCN amplification showed significant correlation with undifferentiated tumors (chi-square test, P = 0.002 and 0.03, respectively). Highly significant correlation was found between the higher mitotic karyorrhectic index (MKI) and MYCN amplification (chi-square test, P < 0.001), whereas neither 1p36 deletion nor 1p36 imbalance significantly correlated with a higher MKI (chi-square test, P > 0.05). We conclude that 1p36 deletion may be a reliable parameter in determining unfavorable histology and predicting prognosis in NB. Further studies with prognostic data are needed to highlight its clinical significance.

Analysis of needle versus open biopsy for the diagnosis of advanced stage pediatric neuroblastoma

BACKGROUND

Adequate tissue biopsy is necessary for the appropriate diagnosis and risk stratification of pediatric neuroblastoma (NB). We compared the quality and adequacy of biopsy tissue and complication rates in children with NB who underwent open (OBX) and image-guided needle biopsy (NBX) at our center.

METHODS

We retrospectively reviewed all patients diagnosed with stage III and IV NB from September 2001 to August 2004. The 24 patients were divided into two groups: those in whom the diagnosis was initiated using NBX, and those diagnosed using OBX. In addition to demographic data, we collected data pertaining to sufficiency of biopsy tissue for biology studies including: Shimada Classification, MYC-N amplification, and DNA index analysis and complications associated with the procedure. Chi-Square and Student's t-test were used to analyze the categorical and continuous variables, respectively.

RESULTS

Of 24 patients, 11 underwent NBX, and 13 patients underwent OBX. Eighteen patients had stage IV disease, 5 patients had stage III disease, and 1 stage IVS. Ten major complications occurred in four NBX patients and six OBX patients. There was no difference in days of narcotic use, time to DAT, or hospital stay between the two groups. Ten patients (seven NBX and three OBX, P = 0.045) had tissue that was insufficient for biology studies. Three of the seven NBX patients underwent a second biopsy for clarification of risk group.

CONCLUSIONS

This study demonstrated that more than half of patients undergoing NBX for NB had insufficient tissue for complete histological and molecular classification and that the incidence of procedural complications between NBX and OBX are similar.

[Genomic profile in high risk neuroblastoma by comparative genomic hybridization]

Different subtypes of neuroblastoma (NB) carry associated genetic aberrations that predict their clinical course. Whole chromosome gains are usually associated with early clinical stages and good prognosis, while 1p deletion, 17q gain and MYCN amplification (MNA) are related to advanced stages and poor prognosis. High-risk neuroblastomas (NB-HR) include NB in children aged more than 1 year old, either stage 4 or any stages showing MNA except stage 1. The prognosis of NB-HR patients remains poor, despite aggressive therapy. Only MNA confers poor prognosis. Between January 2000 and February 2005, tumoral specimens from 60 patients with NB-HR were sent to the Spanish Reference Center for NB biological studies. In all cases, MYCN together with 1p36 status was analyzed by fluorescence in situ hybridization (FISH). Comparative genomic hybridization (CGH) was performed in 24 cases. Using FISH we detected 31 MNA cases including 29 with 1p36 deletion; there were 21 cases without MYCN amplification (MNNA) but 7 of these had 1p36 deletion; 8 cases showed MYCN gain (MNG) but 6 of these had 1p36 deletion. CGH showed other chromosomal alterations. Of 11 MNA cases, none had 11q loss and all of them showed 17q gain or 17 disomy. Of the 7 MNNA cases, there were 4 with 11q loss including 2 with 3p loss and all presented 17q gain or 17 disomy. The 6 MNG cases included 4 cases with 11q loss and 5 cases with 17q gain or 17 disomy. Genomic profiling by CGH in NB-HR confirms the interaction among genetic alterations, the prognostic significance of which should be evaluated to establish new treatment criteria.

Prognostic significance of gene expression profiles of metastatic neuroblastomas lacking MYCN gene amplification

BACKGROUND

The aggressiveness of metastatic neuroblastomas that lack MYCN gene amplification varies with age--they are least aggressive when diagnosed in patients younger than 12 months and most aggressive when diagnosed in patients older than 24 months. However, age at diagnosis is not always associated with patient survival. We examined whether molecular classification of metastatic neuroblastomas without MYCN gene amplification at diagnosis using gene expression profiling could improve the prediction of risk of disease progression.

METHODS

We used Affymetrix microarrays to determine the gene expression profiles of 102 untreated primary neuroblastomas without MYCN gene amplification obtained from children whose ages at diagnosis ranged from 0.1 to 151 months. A supervised method using diagonal linear discriminant analysis was devised to build a multigene model for predicting risk of disease progression. The accuracy of the model was evaluated using nested cross-validations, permutation analyses, and gene expression data from 15 additional tumors obtained at disease progression.

RESULTS

An expression profile model using 55 genes defined a tumor signature that distinguished two groups of patients from among those older than 12 months at diagnosis and clinically classified as having high-risk disease, those with a progression-free survival (PFS) rate of 16% (95% confidence interval [CI] = 8% to 28%), and those with a PFS rate of 79% (95% CI = 57% to 91%) (P<.01). These tumor signatures also identified two groups of patients with PFS of 15% (95% CI = 7% to 27%) and 69% (95% CI = 40% to 86%) (P<.01) from among patients who were older than 18 months at diagnosis. The gene expression signature of untreated molecular high-risk tumors was also present in progressively growing tumors.

CONCLUSION

Gene expression signatures of tumors obtained at diagnosis from patients with clinically indistinguishable high-risk, metastatic neuroblastomas identify subgroups with different outcomes. Accurate identification of these subgroups with gene expression profiles may facilitate development, implementation, and analysis of clinical trials aimed at improving outcome.

Somatic stem cells and the origin of cancer

Most human cancers derive from a single cell targeted by genetic and epigenetic alterations that initiate malignant transformation. Progressively, these early cancer cells give rise to different generations of daughter cells that accumulate additional mutations, acting in concert to drive the full neoplastic phenotype. As we have currently deciphered many of the gene pathways disrupted in cancer, our knowledge about the nature of the normal cells susceptible to transformation upon mutation has remained more elusive. Adult stem cells are those that show long-term replicative potential, together with the capacities of self-renewal and multi-lineage differentiation. These stem cell properties are tightly regulated in normal development, yet their alteration may be a critical issue for tumorigenesis. This concept has arisen from the striking degree of similarity noted between somatic stem cells and cancer cells, including the fundamental abilities to self-renew and differentiate. Given these shared attributes, it has been proposed that cancers are caused by transforming mutations occurring in tissue-specific stem cells. This hypothesis has been functionally supported by the observation that among all cancer cells within a particular tumor, only a minute cell fraction has the exclusive potential to regenerate the entire tumor cell population; these cells with stem-like properties have been termed cancer stem cells. Cancer stem cells can originate from mutation in normal somatic stem cells that deregulate their physiological programs. Alternatively, mutations may target more committed progenitor cells or even mature cells, which become reprogrammed to acquire stem-like functions. In any case, mutated genes should promote expansion of stem/progenitor cells, thus increasing their predisposition to cancer development by expanding self-renewal and pluripotency over their normal tendency towards relative quiescency and proper differentiation.