Neuroblastoma: biology, prognosis, and treatment

Retroperitoneal neoplasms within the perirenal space in infants and children: differentiation of renal and non-renal origin in enhanced CT images

PURPOSE

To retrospectively demonstrate the specific CT findings of retroperitoneal neoplasms to diagnosis and differential diagnosis renal and non-renal tumors within the perirenal space in infants and children.

MATERIALS AND METHODS

We retrospectively reviewed the clinical data and CT images of 42 consecutive patients with surgically and pathologically proven retroperitoneal neoplasms within the perirenal space. The patients were divided into renal tumors group (n=16) and non-renal tumors group (n=26). The former included nephroblastoma (n=15) and renal lymphoma (n=1), while the latter included neuroblastoma (n=12), retroperitoneal teratoma (n=6), adrenal ganglioneuroma (n=4), retroperitoneal lymphoma (n=2), ectopic pheochromocytoma (n=1) and adrenal cortical carcinoma (n=1). The clinical information of these patients and the major CT imaging findings which were related to lesion localization in the two groups were compared and statistically analyzed using Pearson Chi-Square Test and Risk Estimate.

RESULTS

The mean diameter of tumors was 9.82±6.13 cm (n=42 range: 2.3-3 2cm). The demographic data and chief clinical symptoms between the renal tumor group and the non-renal tumor group showed no statistically significant differences (P>0.05). 30.8% (8/26) of non-renal tumor patients presented elevated urinary vanillylmandelic acid (VMA) level, while no patient showed elevated VMA in renal tumor group (P<0.05). Some CT imaging signs of the renal tumors including "crescent sign" (odds ratio, OR=52), "beak sign" (OR=84), "embedded organ sign" (OR=84), and "prominent feeding artery sign" (OR=36) showed significantly higher incidence when compared to the non-renal tumors (P<0.001). The sign of "renal displacement and renal axis rotation" (OR=0.059) was seen in 23 of 26 (88.5%) non-renal tumors, but in only 5 of 16 (31.3%) renal tumors (P<0.001). The sign of "extra-renal central plane of tumor" (OR=0.038) was displayed in 24 of 26 (92.3%) non-renal tumors, but in only 5 of 16 (31.3%) renal tumors (P<0.001). The CT findings such as "pseudocapsule" (OR=38.5), "necrosis and cystic change" (OR=11.2), "vascularity" (OR=16.867), "distant metastasis" (OR=5.96), and "inferior vena cava tumor thrombus" which were thought to be characteristic of renal tumors were observed with significant higher incidence in renal tumors group than in the non-renal tumors group (P<0.05); while CT signs of "irregular mass" (OR=0.045) and "intratumoral calcifications" (OR=0.065) were observed with lower incidence in renal tumors group than in the non-renal tumors group (P<0.05).

CONCLUSION

The "crescent sign", "beak sign", "embedded kidney sign" and "renal arteries feeding" are the most specific CT signs suggestive of renal tumors and distinguish them from non-renal origin tumors within the perirenal space. Other CT signs, such as "pseudocapsule", "hypervascular tumors" and "Inferior vena cava tumor thrombus", when present, tumors of renal origin are strongly suggested. On the other hand, CT signs of "irregular mass", "intratumoral calcifications", and associated elevated urinary vanillylmandelic acid strongly suggest the non-renal tumors.

Kabuki syndrome and cancer in two patients

Both hepatoblastoma and neuroblastoma are occasionally associated with congenital syndromes such as Beckwith-Wiedemann syndrome and trisomy 18. There have been no reports of hepatoblastoma in patients with Kabuki syndrome, whereas one patient with neuroblastoma and this syndrome has been reported. In this paper we present two patients with Kabuki syndrome and a neoplasm: a child of 6 years with hepatoblastoma and an infant, of 6 months affected by neuroblastoma.

Pharmacotherapy of neuroblastoma

IMPORTANCE OF THE FIELD

Neuroblastoma, a tumor of the sympathetic nervous system, is the most common extracranial solid tumor of early life. High risk disease in older children remains a therapeutic challenge, despite high-intensity therapy with correspondingly significant short- and long-term toxicities.

AREAS COVERED IN THIS REVIEW

We have reviewed therapy for neuroblastoma over the last three decades. This includes cytotoxic chemotherapy, immunotherapy, radionuclides, antiangiogenic compounds, and molecularly targeted agents. We provide a perspective on the incorporation of these drugs into therapy for neuroblastoma.

WHAT THE READER WILL GAIN

The reader will gain a better understanding of these novel agents and their targets in neuroblastoma. The reader will also gain insight into the need to define through sequential, carefully designed clinical trials, the roles and toxicities of these therapies, especially if the combination of targeted and conventional cytotoxic agents is used.

TAKE HOME MESSAGE

Advanced-stage neuroblastoma in older infants and children remains a disease that is difficult to cure. New, targeted agents may improve both the therapeutic index and the outcome, but are, for the most part, in early development and present a challenge for clinical trial design given both the rarity of this disease and its responsiveness (albeit incomplete) to currently used cytotoxic agents.

Neuropeptide Y and its Y2 receptor: potential targets in neuroblastoma therapy

Neuroblastomas are pediatric tumors which develop from sympathetic precursors and express neuronal proteins, such as neuropeptide Y (NPY). NPY is a sympathetic neurotransmitter acting via multiple receptors (Y1-Y5R). Both NPY and Y2Rs are commonly expressed in neuroblastoma cell lines and tissues. The peptide secreted from neuroblastomas stimulates tumor cell proliferation and angiogenesis. Since both processes are Y2R-mediated, the goal of this study was to assess Y2R as a potential therapeutic target for neuroblastoma. In vitro, Y2R antagonist (BIIE0246) prevented activation of p44/42 MAPK induced by endogenous NPY, which resulted in decreased proliferation and induction of Bim-mediated apoptosis. Similar growth-inhibitory effects were achieved with NPY siRNA and Y2R siRNA. In vivo, Y2R antagonist significantly inhibited growth of SK-N-BE(2) and SK-N-AS xenografts, which was associated with decreased activation of p44/42 MAPK, as well as reduced proliferation (Ki67) and increased apoptosis (TUNEL). The Y2R antagonist also exerted an anti-angiogenic effect. In vitro, it reduced the proliferation of endothelial cells induced by neuroblastoma-conditioned media. Consequently, the Y2R antagonist-treated xenografts had decreased vascularization and a high degree of focal fibrosis. In human neuroblastoma tissues, the expression of Y2R was observed in both tumor and endothelial cells, while NPY was predominantly expressed in neuroblastoma cells. In summary, Y2R is a promising new target for neuroblastoma therapy affecting both cancer cells and tumor vasculature.

Isolated central nervous system recurrence in a child with stage IV neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in children. Survival rates have improved due to advances in treatment with aggressive chemotherapy and autologous bone marrow transplantation. Usual sites of recurrence include the site of primary tumor, residual gross disease, bone, bone narrow, liver, and lungs. The authors describe a 16-month-old boy with stage IV extracerebral primary neuroblastoma who died because of an isolated central nervous system (CNS) relapse. The CNS is a rare site of relapse that is, however, increasingly diagnosed due to prolonged survival. Criteria to identify patients at increased risk of CNS relapse are urgently needed. High-risk patients should be followed-up with brain and spine magnetic resonance imaging (MRI) for timely detection of metastases and appropriate management.

A composite pheochromocytoma/ganglioneuroblastoma of the adrenal gland

A 9-year-old female presented with a large abdominal mass. At surgery, the mass was noted to arise from the right adrenal gland. As the mass was manipulated, the patient developed severe hypertension. The final diagnosis was a cystic composite-pheochromocytoma/ganglioneuroblastoma. This compound adrenal tumor is only the fourth case reported in a child. Because composite pheochromocytomas are rare in the pediatric population, the management, optimal surveillance schedule and outcomes have not been characterized.

Enhancement of vinorelbine-induced cytotoxicity and apoptosis by clomipramine and lithium chloride in human neuroblastoma cancer cell line SH-SY5Y

The aim of this work is to investigate whether clomipramine (CIM) and lithium chloride (LiCl) potentiate the cytotoxicity of vinorelbine (VNR) on SH-SY5Y human neuroblastoma cells in vitro and whether midkine (MK) can be a resistance factor for these treatments. Four groups of experiments were performed for 96 h using both monolayer and spheroid cultures of SH-SY5Y cells: (1) control group, (2) singly applied VNR, CIM, and LiCl, (3) VNR with CIM, and (4) VNR with LiCl. Their effects on monolayer and spheroid cultures were determined by evaluating cell proliferation, bromodeoxyuridine labeling index (BrdU-LI), apoptosis, cyclic adenosine monophosphate (cAMP) and midkine levels, colony-forming efficiency, spheroid size, and ultrastructure. In comparison with the control group, single and combination drug treatments significantly reduced the proliferation index (PI) for 96 h. The most potent reduction of PI was observed with VNR in combination with CIM and LiCl for all time intervals. VNR with CIM and LiCl seemed to be ineffective in reducing BrdU-LI of both monolayer cell and spheroid cultures, spheroid size, and cAMP level. VNR with LiCl increased apoptosis at 24 h, however VNR with CIM increased apoptosis at 96 h. VNR was the most potent drug in inhibiting colony-forming efficiency. The combination of VNR with CIM was the most potent in reducing midkine levels among all groups. Interestingly, the combination of VNR with LiCl led to both nuclear membrane breakdown and disappearance of the cellular membranes inside the spheroids. Both CIM and LiCl seemed to potentiate VNR-induced cytotoxicity, and MK was not a resistance factor for VNR, LiCl, and CIM.

The Hox genes and their roles in oncogenesis

Hox genes, a highly conserved subgroup of the homeobox superfamily, have crucial roles in development, regulating numerous processes including apoptosis, receptor signalling, differentiation, motility and angiogenesis. Aberrations in Hox gene expression have been reported in abnormal development and malignancy, indicating that altered expression of Hox genes could be important for both oncogenesis and tumour suppression, depending on context. Therefore, Hox gene expression could be important in diagnosis and therapy.

The studies on the correlation for gene expression of tyrosine-kinase receptors and vascular endothelial growth factor in human neuroblastomas

OBJECTIVE

To study the correlation and clinical significance of expression of tyrosine-kinase receptors (TrkA and TrkB) and vascular endothelial growth factor (VEGF) in human neuroblastomas.

METHODS

Expression of TrkA, TrkB, and VEGF mRNA was semi-quantitatively detected by reverse transcription-polymerase chain reaction (RT-PCR) in 51 cases of neuroblastomas.

RESULTS

The expression of TrkA was significantly higher in lower-stage group compared with higher-stage group (P<0.05), whereas the expression of VEGF was significantly higher in the higher-stage group compared with the lower-stage group (P<0.05). The expression of TrkA was correlated negatively with the expression of VEGF (P<0.01), and has remarkable dependability with 2-year cumulative survival rate (P<0.01). The expression of TrkA in the lower age group was significantly higher than in the higher age group of NB cases (P<0.01). TrkA has a good prognostic impact on neuroblastoma patients (P<0.01). The expression of TrkB was significantly higher in the higher-stage group compared with the lower-stage group (P<0.05) and was positively correlated with VEGF expression (r=0.342, P<0.05); their expression also has remarkable dependability with the 2-year cumulative survival rate (P<0.01). The expression of TrkB was significantly lower in the higher age group compared with the lower age group (P<0.05). The 2-year cumulative-survival rate in the lower age group had a great significance compared with the higher age group (P<0.001). TrkB has a bad prognostic impact on neuroblastoma patients (P<0.01).

CONCLUSIONS

TrkA was highly expressed in good prognostic neuroblastomas; however, TrkB and VEGF were highly expressed in poor prognostic neuroblastomas. The expression of TrkA was negatively correlated with the expression of VEGF, whereas the expression of TrkB was positively correlated with the expression of VEGF. These 3 genes have an important clinical significance relating to the tumor stage and the outcome for patients with neuroblastomas.

Genistein induces receptor and mitochondrial pathways and increases apoptosis during BCL-2 knockdown in human malignant neuroblastoma SK-N-DZ cells

The potent antiapoptotic molecule Bcl-2 is markedly up-regulated in a majority of cancers, including neuroblastoma. Genistein is an isoflavone with antitumor properties. The present study sought to elucidate the molecular mechanism of genistein-induced apoptosis and also to examine the effect of genistein in increasing apoptosis during Bcl-2 knockdown in human malignant neuroblastoma SK-N-DZ cells. The cells were transfected with Bcl-2 siRNA plasmid vector, treated with 10 microM genistein, or the combination, and subjected to TUNEL staining and FACS analysis. Semiquantitative and real-time RT-PCR experiments were performed for examining expression of Fas ligand (FasL), tumor necrosis factor-alpha (TNF-alpha), Fas-associated death domain (FADD), and TNFR-1-associated death domain (TRADD). The cell lysates were analyzed by Western blotting for levels of molecules involved in both receptor- and mitochondria-mediated apoptotic pathways. Treatment with the combination of Bcl-2 siRNA and genistein resulted in more than 80% inhibition of cell proliferation. TUNEL staining and FACS analysis demonstrated apoptosis in 70% of cells after treatment with the combination of both agents. Apoptosis was associated with increases in Bax:Bcl-2 ratio, mitochondrial release of cytochrome c, and activation of caspases through the mitochondria-mediated apoptotic pathway. Genistein triggered the receptor-mediated apoptotic pathway through upregulation of TNF-alpha, FasL, TRADD, and FADD and activation of caspase-8. Combination of Bcl-2 siRNA and genistein triggered a marked increase in cleavage of DFF45 and PARP that resulted in enhanced apoptosis. Our study demonstrates that Bcl-2 knockdown during genistein treatment effectively induced apoptosis in neuroblastoma cells. Therefore, this strategy could serve as a potential therapeutic regimen to inhibit the growth of human malignant neuroblastoma.

Myc proteins as therapeutic targets

Myc proteins (c-myc, Mycn and Mycl) target proliferative and apoptotic pathways vital for progression in cancer. Amplification of the MYCN gene has emerged as one of the clearest indicators of aggressive and chemotherapy-refractory disease in children with neuroblastoma, the most common extracranial solid tumor of childhood. Phosphorylation and ubiquitin-mediated modulation of Myc protein influence stability and represent potential targets for therapeutic intervention. Phosphorylation of Myc proteins is controlled in-part by the receptor tyrosine kinase/phosphatidylinositol 3-kinase/Akt/mTOR signaling, with additional contributions from Aurora A kinase. Myc proteins regulate apoptosis in part through interactions with the p53/Mdm2/Arf signaling pathway. Mutation in p53 is commonly observed in patients with relapsed neuroblastoma, contributing to both biology and therapeutic resistance. This review examines Myc function and regulation in neuroblastoma, and discusses emerging therapies that target Mycn.

The anti-apoptotic protein BCL2L1/Bcl-xL is neutralized by pro-apoptotic PMAIP1/Noxa in neuroblastoma, thereby determining bortezomib sensitivity independent of prosurvival MCL1 expression

Neuroblastoma is the most frequent extracranial solid tumor in children. Here, we report that the proteasome inhibitor bortezomib (PS-341, Velcade) activated the pro-apoptotic BH3-only proteins PMAIP1/Noxa and BBC3/Puma and induced accumulation of anti-apoptotic MCL1 as well as repression of anti-apoptotic BCL2L1/Bcl-xL. Retroviral expression of Bcl-xL, but not of MCL1, prevented apoptosis by bortezomib. Gene knockdown of Noxa by shRNA technology significantly reduced apoptosis, whereas Puma knockdown did not affect cell death kinetics. Immunoprecipitation revealed that endogenous Noxa associated with both, Bcl-xL and MCL1, suggesting that in neuronal cells Noxa can neutralize Bcl-xL, explaining the pronounced protective effect of Bcl-xL. Tetracycline-regulated Noxa expression did not trigger cell death per se but sensitized to bortezomib treatment in a dose-dependent manner. This implies that the induction of Noxa is necessary but not sufficient for bortezomib-induced apoptosis. We conclude that MCL1 steady-state expression levels do not affect sensitivity to proteasome-inhibitor treatment in neuronal tumor cells, and that both the repression of Bcl-xL and the activation of Noxa are necessary for bortezomib-induced cell death.

Synthetic mRNA splicing modulator compounds with in vivo antitumor activity

We report our progress on the development of new synthetic anticancer lead compounds that modulate the splicing of mRNA. We also report the synthesis and evaluation of new biologically active ester and carbamate analogues. Further, we describe initial animal studies demonstrating the antitumor efficacy of compound 5 in vivo. Additionally, we report the enantioselective and diastereospecific synthesis of a new 1,3-dioxane series of active analogues. We confirm that compound 5 inhibits the splicing of mRNA in cell-free nuclear extracts and in a cell-based dual-reporter mRNA splicing assay. In summary, we have developed totally synthetic novel spliceosome modulators as therapeutic lead compounds for a number of highly aggressive cancers. Future efforts will be directed toward the more complete optimization of these compounds as potential human therapeutics.

Neuroblastoma involvement of the falx cerebri

Involvement of the falx cerebri in infants with stage 4 neuroblastoma is thought to be rare. The falx is derived from the neural crest and thus may be a location for primary neuroblastoma. Its propensity for metastasis is unknown. Management of neuroblastoma in this location is potentially challenging. We describe two children less than 18 months of age who were successfully managed with chemotherapy alone (without radiation or surgery) for falx involvement with neuroblastoma.

High-risk neuroblastoma: a therapy in evolution

High-risk neuroblastoma remains a therapeutic challenge for pediatric oncologists. It is becoming increasingly evident that conventional chemotherapeutics are approaching or perhaps have already attained their maximum therapeutic potential. The focus of this review is to summarize current therapies and bring to light some of the novel strategies for treating high-risk neuroblastoma. These rationally designed therapies include molecular- and immune-targeted agents in an attempt to exploit the biology of the neuroblastoma cell. These novel therapies are likely to pose a whole new set of challenges and questions and emphasize the need for continued enrollment of patients in therapeutic studies.

Enteric neural crest differentiation in ganglioneuromas implicates Hedgehog signaling in peripheral neuroblastic tumor pathogenesis

Peripheral neuroblastic tumors (PNTs) share a common origin in the sympathetic nervous system, but manifest variable differentiation and growth potential. Malignant neuroblastoma (NB) and benign ganglioneuroma (GN) stand at opposite ends of the clinical spectrum. We hypothesize that a common PNT progenitor is driven to variable differentiation by specific developmental signaling pathways. To elucidate developmental pathways that direct PNTs along the differentiation spectrum, we compared the expression of genes related to neural crest development in GN and NB. In GNs, we found relatively low expression of sympathetic markers including adrenergic biosynthesis enzymes, indicating divergence from sympathetic fate. In contrast, GNs expressed relatively high levels of enteric neuropeptides and key constituents of the Hedgehog (HH) signaling pathway, including Dhh, Gli1 and Gli3. Predicted HH targets were also differentially expressed in GN, consistent with transcriptional response to HH signaling. These findings indicate that HH signaling is specifically active in GN. Together with the known role of HH activity in enteric neural development, these findings further suggested a role for HH activity in directing PNTs away from the sympathetic lineage toward a benign GN phenotype resembling enteric ganglia. We tested the potential for HH signaling to advance differentiation in PNTs by transducing NB cell lines with Gli1 and determining phenotypic and transcriptional response. Gli1 inhibited proliferation of NB cells, and induced a pattern of gene expression that resembled the differential pattern of gene expression of GN, compared to NB (p<0.00001). Moreover, the transcriptional response of SY5Y cells to Gli1 transduction closely resembled the transcriptional response to the differentiation agent retinoic acid (p<0.00001). Notably, Gli1 did not induce N-MYC expression in neuroblastoma cells, but strongly induced RET, a known mediator of RA effect. The decrease in NB cell proliferation induced by Gli1, and the similarity in the patterns of gene expression induced by Gli1 and by RA, corroborated by closely matched gene sets in GN tumors, all support a model in which HH signaling suppresses PNT growth by promoting differentiation along alternative neural crest pathways.

Pegfilgrastim for prevention of chemotherapy-associated neutropenia in pediatric patients with solid tumors

BACKGROUND

Pegfilgrastim has similar efficacy to filgrastim in adults, but studies in pediatrics are limited. We report our institutional experience with pegfilgrastim following dose intensive chemotherapy for solid tumors.

PROCEDURE

We evaluated the initial four courses of myelosuppressive chemotherapy for 47 patients (total 176 courses) diagnosed between 1/1/07 and 2/6/08 who received chemotherapy with pegfilgrastim support (100 mcg/kg; 6 mg maximum dose) in this retrospective review. We collected demographic data, treatment characteristics, frequency of severe neutropenia (absolute neutrophil count (ANC) <200/mm(3)), duration of neutropenia, and frequency of neutropenic fever.

RESULTS

The median age of treated patients was 13 years (range 0.17-23 years) and the median weight was 50.8 kg (range 4-107 kg), including 16 (34%) <20 kg, and 22 (47%) <45 kg. Primary diagnoses included osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, soft tissue sarcoma, neuroblastoma, Hodgkin disease, and other solid tumors. No significant adverse events secondary to pegfilgrastim were noted. Severe neutropenia occurred in 57% of courses. The median duration of severe neutropenia was 1 day (range 0-11 days). Febrile neutropenia occurred in 28% of courses. Eight patients were treated with interval-compressed (every 14 days) sarcoma chemotherapy. Of the 30-interval compressed courses, the median duration per course was 14 days (range 14-18 days).

CONCLUSIONS

Pegfilgrastim following dose intensive chemotherapy for solid tumors is feasible in children, including those <45 kg. The frequency and duration of severe neutropenia, as well as incidence of febrile neutropenia, were similar to filgrastim historic data.

New therapeutic targets for the treatment of high-risk neuroblastoma

High-risk neuroblastoma remains a major problem in pediatric oncology, accounting for 15% of childhood cancer deaths. Although incremental improvements in outcome have been achieved with the intensification of conventional chemotherapy agents and the addition of 13-cis-retinoic acid, only one-third of children with high-risk disease are expected to be long-term survivors when treated with current regimens. In addition, the cost of cure can be quite high, as surviving children remain at risk for additional health problems related to long-term toxicities of treatment. Further advances in therapy will require the targeting of tumor cells in a more selective and efficient way so that survival can be improved without substantially increasing toxicity. In this review we summarize ongoing clinical trials and highlight new developments in our understanding of the molecular biology of neuroblastoma, emphasizing potential targets or pathways that may be exploitable therapeutically.

Anaplastic lymphoma kinase: role in cancer pathogenesis and small-molecule inhibitor development for therapy

Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase in the insulin receptor superfamily, was initially identified in constitutively activated oncogenic fusion forms - the most common being nucleophosmin-ALK - in anaplastic large-cell lymphomas, and subsequent studies have identified ALK fusions in diffuse large B-cell lymphomas, systemic histiocytosis, inflammatory myofibroblastic tumors, esophageal squamous cell carcinomas and non-small-cell lung carcinomas. More recently, genomic DNA amplification and protein overexpression, as well as activating point mutations, of ALK have been described in neuroblastomas. In addition to those cancers for which a causative role for aberrant ALK activity is well validated, more circumstantial links implicate the full-length, normal ALK receptor in the genesis of other malignancies - including glioblastoma and breast cancer - via a mechanism of receptor activation involving autocrine and/or paracrine growth loops with the reported ALK ligands, pleiotrophin and midkine. This review summarizes normal ALK biology, the confirmed and putative roles of ALK in the development of human cancers and efforts to target ALK using small-molecule kinase inhibitors.

A gastrin-releasing peptide receptor antagonist stimulates Neuro2a neuroblastoma cell growth: prevention by a histone deacetylase inhibitor

Gastrin-releasing peptide (GRP) acts as an autocrine growth factor for neuroblastoma and other types of cancer, and its cell-surface receptor, GRPR, is overexpressed in advanced-stage human neuroblastoma. GRPR knockdown and GRPR antagonism inhibit the growth of experimental neuroblastoma. Here we show that a GRPR antagonist promotes rather than inhibits the growth of neuroblastoma cells. The GRPR antagonist, RC-3095, at 0.1 nM inhibited, whereas at 100 nM stimulated proliferation of Neuro2a murine neuroblastoma cells in vitro. The stimulatory effects were prevented by the histone deacetylase inhibitor (HDACi), sodium butyrate (NaB). Expression of GRPR mRNA in Neuro2a cells was analyzed by RT-PCR. These findings provide evidence that a GRPR antagonist can stimulate the growth of cancer cells, and suggest that GRPR might interact with epigenetic mechanisms in regulating neuroblastoma cell growth.

Survival trends in children with hepatoblastoma

PURPOSE

Hepatoblastoma (HB) is a relatively rare pediatric malignancy. In this study, we present demographic data and a survival analysis from the largest patient cohort with HB reported to date.

METHODS

The surveillance, epidemiology, and end results database was queried from 1973 to 2005 for all patients diagnosed with HB. Kaplan-Meier survival analysis was conducted to determine actuarial survival. Cox regression analysis was performed to determine hazard ratios (HR) for prognostic variables.

RESULTS

During the study period, 459 patients with HB were identified. Overall 1-, 3-, and 5-year survival rates for the entire patient cohort were 76, 63, and 60%, respectively. Five-year survival improved over time from 36 (1973-1982) to 63% (1983-2005). Predictors of poor survival include: age 2 years and greater (HR 1.566), black race (HR 1.910), diagnosis prior to 1983 (HR 3.327), inability to perform surgical resection (HR 3.857), regional disease (HR 1.939), and distant disease (HR 3.196).

CONCLUSIONS

Hepatoblastoma continues to challenge surgeons and oncologists. Most children are diagnosed early in life and undergo surgical resection whenever possible. With the advent of efficacious chemotherapy, survival has improved. Older children, black patients, and those who present with advanced disease tend to have poor outcomes. Surgical resection is the single most important predictor of survival.

Reanalysis of neuroblastoma expression profiling data using improved methodology and extended follow-up increases validity of outcome prediction

Neuroblastoma is the most common extracranial childhood tumor, comprising 15% of all childhood cancer deaths. In an initial study, we used Affymetrix oligonucleotide microarrays to analyse gene expression in 68 primary neuroblastomas and compared different data mining approaches for prediction of early relapse. Here, we performed re-analyses of the data including prolonged follow-up and applied support vector machine (SVM) algorithms and outer cross-validation strategies to improve reliability of expression profiling based predictors. Accuracy of outcome prediction was significantly improved by the use of innovative SVM algorithms on the updated data. In addition, CASPAR, a hierarchical Bayesian approach, was used to predict survival times for the individual patient based on expression profiling data. CASPAR reliably predicted event-free survival, given a cut-off time of three years. Differential expression of genes used by CASPAR to predict patient outcome was validated in an independent cohort of 117 neuroblastomas. In conclusion, we show here for the first time that reanalysis of microarray data using improved methodology, state-of-the-art performance tests and updated follow-up data improves prognosis prediction, and may further improve risk stratification of individual patients.

CpG oligonucleotides for immunotherapeutic treatment of neuroblastoma

Neuroblastoma is the most common extracranial solid tumor malignancy of childhood. Although it is generally responsive to treatment, high risk cases of neuroblastoma frequently recur. The prognosis for relapsed cases is extremely poor despite aggressive therapy. The frequency of relapse and subsequent failure of further treatment has spurred the need to develop non toxic and more effective treatments for targeting residual tumor cells during the phase of minimal residual disease. Traditional cancer therapies are non-specific, leading to the destruction of normal, healthy tissues. Failure to induce specific tumor immunity may be due to several immunosuppressive factors. Primary amongst these factors are: lack of co-stimulatory molecules on the surface of tumor cells, the ability of the tumor to modulate immunity in a suppressive manner and the presence of an immunosuppressive microenvironment at the location of the tumor. Unfortunately, tumor tolerance impedes the ability to establish immunity to tumor antigens and overcoming this tolerance is essential to developing effective tumor immunity. Vaccine strategies that target host immune effector cells with synthetic oligodeoxynucleotides (ODNs) that contain unmethylated CpG motifs (CpG-ODNs) represent a novel approach to overcoming tolerance in cancer therapy. This approach enables biasing of host immunity toward a proinflammatory Th1 and thus anti-tumor response. The addition of immunogenic tumor specific antigen to the CpG-ODN vaccine may allow for specific targeting and killing of established tumors.

Sonographic Evaluation of Neuroblastoma

Neuroblastoma is a malignancy arising from the sympathetic nervous system that accounts for approximately 7% of childhood cancers. Most occur between the ages of 2 months and 2 years. The majority arises in the adrenal medulla but may also occur in the neck, chest, or pelvis. Diagnostic medical sonography is a significant imaging tool that involves no radiation exposure for detecting neuroblastoma. Further imaging studies are needed so that the stage and spread of the disease can be determined. Factors including age, MYCN (v-myc myelocytomatosis viral-related oncogene) amplification, and stage are used to determine treatment and prognosis of a child with neuroblastoma. This case demonstrates the sonographic findings of an 8-month-old child with stage IV neuroblastoma.