Medulloblastoma Down Under 2013: a report from the third annual meeting of the International Medulloblastoma Working Group.

Medulloblastoma is curable in approximately 70% of patients. Over the past decade, progress in improving survival using conventional therapies has stalled, resulting in reduced quality of life due to treatment-related side effects, which are a major concern in survivors. The vast amount of genomic and molecular data generated over the last 5-10 years encourages optimism that improved risk stratification and new molecular targets will improve outcomes. It is now clear that medulloblastoma is not a single-disease entity, but instead consists of at least four distinct molecular subgroups: WNT/Wingless, Sonic Hedgehog, Group 3, and Group 4. The Medulloblastoma Down Under 2013 meeting, which convened at Bunker Bay, Australia, brought together 50 leading clinicians and scientists. The 2-day agenda included focused sessions on pathology and molecular stratification, genomics and mouse models, high-throughput drug screening, and clinical trial design. The meeting established a global action plan to translate novel biologic insights and drug targeting into treatment regimens to improve outcomes. A consensus was reached in several key areas, with the most important being that a novel classification scheme for medulloblastoma based on the four molecular subgroups, as well as histopathologic features, should be presented for consideration in the upcoming fifth edition of the World Health Organization's classification of tumours of the central nervous system. Three other notable areas of agreement were as follows: (1) to establish a central repository of annotated mouse models that are readily accessible and freely available to the international research community; (2) to institute common eligibility criteria between the Children's Oncology Group and the International Society of Paediatric Oncology Europe and initiate joint or parallel clinical trials; (3) to share preliminary high-throughput screening data across discovery labs to hasten the development of novel therapeutics. Medulloblastoma Down Under 2013 was an effective forum for meaningful discussion, which resulted in enhancing international collaborative clinical and translational research of this rare disease. This template could be applied to other fields to devise global action plans addressing all aspects of a disease, from improved disease classification, treatment stratification, and drug targeting to superior treatment regimens to be assessed in cooperative international clinical trials.

Biological and clinical heterogeneity of MYCN-amplified medulloblastoma.

Focal high-level amplifications of MYC (or MYCC) define a subset of high-risk medulloblastoma patients. However, the prognostic role of MYCN oncogene amplification remains unresolved. We aimed to evaluate the prognostic value of this alteration alone and in combination with biological modifiers in 67 pediatric medulloblastomas with MYCN amplification (MYCN-MB). Twenty-one MYCN-MB were examined using gene expression profiling and array-CGH, whereas for 46 tumors immunohistochemical analysis and FISH were performed. All 67 tumors were further subjected to mutational analyses. We compared molecular, clinical, and prognostic characteristics both within biological MYCN-MB groups and with non-amplified tumors. Transcriptomic analysis revealed SHH-driven tumorigenesis in a subset of MYCN-MBs indicating a biological dichotomy of MYCN-MB. Activation of SHH was accompanied by variant-specific cytogenetic aberrations including deletion of 9q in SHH tumors. Non-SHH MB were associated with gain of 7q and isochromosome 17q/17q gain. Among clinically relevant variables, SHH subtype and 10q loss for non-SHH tumors comprised the most powerful markers of favorable prognosis in MYCN-MB. In conclusion, we demonstrate considerable heterogeneity within MYCN-MB in terms of genetics, tumor biology, and clinical outcome. Thus, assessment of disease group and 10q copy-number status may improve risk stratification of this group and may delineate MYCN-MB with the same dismal prognosis as MYC amplified tumors. Furthermore, based on the enrichment of MYCN and GLI2 amplifications in SHH-driven medulloblastoma, amplification of these downstream signaling intermediates should be taken into account before a patient is enrolled into a clinical trial using a smoothened inhibitor.

Integration of needle-free jet injection with advanced electroporation delivery enhances the magnitude, kinetics, and persistence of engineered DNA vaccine induced immune responses.

The combination of optimized DNA constructs, improved formulations and advanced in vivo electroporation (EP) has been shown to generate potent and efficacious immune responses in the clinic. Needle-free jet injection has also been reported to improve DNA vaccine delivery over standard needle and syringe in clinical trials. Here we investigated the impact of combined jet injection and EP (Jet-EP) delivery on muscle transfection efficiency and DNA vaccine immunogenicity in rabbits and nonhuman primates (NHPs) compared to jet injection alone. Our results show that the addition of EP significantly enhanced in vivo DNA transfection efficiency of rabbit muscle over jet injection alone. Jet-EP delivery augmented the rate and magnitude of DNA vaccine induced humoral and cellular responses over jet injection alone in both rabbits and NHPs. Jet-EP delivery also resulted in higher proportions of polyfunctional antigen specific T cells producing IFNγ, IL-2, and/or TNFα. Elevated antibody levels were sustained nine months post immunization in NHPs immunized with a DNA vaccine using Jet-EP delivery, far outperforming jet delivery alone. Our results provide proof-of-concept that addition of advanced EP to needle-free jet injection delivery improves in vivo DNA transfection efficiency, increasing the magnitude, rate and duration of cellular and humoral immune responses to DNA vaccines. This combination likely has significant advantages in important vaccine and immunotherapy settings.

Dental caries trends in primary teeth among third-grade children in Harris County, Texas.

PURPOSE: The purpose of this study was to assess trends in dental caries in the primary dentition of third-grade children in suburban Harris County, Texas. METHODS: The study populations for the 2 cross-sectional surveys consisted of 1,584 third-grade children in 1991 and 1,039 in 1998. Trained dentists collected data on decayed and filled tooth surfaces (dfs). Chi-square tests analyzed the differences in proportions of children with and without dental caries experience in 1991 and 1998 by demographic subgroups: (1) gender; (2) ethnicity; and (3) socioeconomic status (SES). Student's t test investigated the differences in mean dfs scores in subgroups. RESULTS: The prevalence of caries decreased significantly from 59% to 54% between 1991 and 1998 (P = .01). The caries prevalence was lower in 1998 than 1991 in certain subgroups: 1) females; 2) Caucasians; and 3) low SES. The mean dfs score decreased significantly from 4.81 to 3.16, and lower dfs scores were seen in certain demographic subgroups between the 2 studies (P < .05). Children from a low SES had high levels of untreated caries in both studies. CONCLUSIONS: Despite a decline in primary teeth caries of study participants, intergroup disparities exist, emphasizing the need for preventive strategies, especially for the low SES children.

Comparative genomic hybridization and BUB1B mutation analyses in childhood cancers associated with mosaic variegated aneuploidy syndrome.

We previously demonstrated that constitutional BUB1B mutations cause mosaic variegated aneuploidy, a condition characterized by constitutional aneuploidies and childhood cancer predisposition. To further investigate the role of BUB1B in cancer predisposition we performed comparative genomic hybridization analysis in an embryonal rhabdomyosarcoma from an MVA case with biallelic BUB1B mutations, revealing aneuploidies typical of sporadic E-RMS, with gain of chromosomes 3, 8, 13 and loss of chromosomes 9, 14, X. To investigate whether somatic BUB1B mutations occur in sporadic childhood cancers we screened 30 Wilms tumours, 10 acute lymphoblastic leukemias, nine rhabdomyosarcomas and 11 rhabdomyosarcoma cell lines for BUB1B mutations. We identified seven exonic and six intronic variants. Six of the exonic variants were synonymous and one resulted in a non-synonymous conservative missense alteration that was also present in a control. These data suggest that the genetic progression in rhabdomyosarcoma from MVA and non-MVA cases may be similar, but that somatic BUB1B mutations are unlikely to be common in sporadic childhood cancers known to be associated with MVA.

Identification of a dynamic core transcriptional network in t(8;21) AML that regulates differentiation block and self-renewal.

Oncogenic transcription factors such as RUNX1/ETO, which is generated by the chromosomal translocation t(8;21), subvert normal blood cell development by impairing differentiation and driving malignant self-renewal. Here, we use digital footprinting and chromatin immunoprecipitation sequencing (ChIP-seq) to identify the core RUNX1/ETO-responsive transcriptional network of t(8;21) cells. We show that the transcriptional program underlying leukemic propagation is regulated by a dynamic equilibrium between RUNX1/ETO and RUNX1 complexes, which bind to identical DNA sites in a mutually exclusive fashion. Perturbation of this equilibrium in t(8;21) cells by RUNX1/ETO depletion leads to a global redistribution of transcription factor complexes within preexisting open chromatin, resulting in the formation of a transcriptional network that drives myeloid differentiation. Our work demonstrates on a genome-wide level that the extent of impaired myeloid differentiation in t(8;21) is controlled by the dynamic balance between RUNX1/ETO and RUNX1 activities through the repression of transcription factors that drive differentiation.

PAX3/FOXO1 fusion gene status is the key prognostic molecular marker in rhabdomyosarcoma and significantly improves current risk stratification.

PURPOSE: To improve the risk stratification of patients with rhabdomyosarcoma (RMS) through the use of clinical and molecular biologic data. PATIENTS AND METHODS: Two independent data sets of gene-expression profiling for 124 and 101 patients with RMS were used to derive prognostic gene signatures by using a meta-analysis. These and a previously published metagene signature were evaluated by using cross validation analyses. A combined clinical and molecular risk-stratification scheme that incorporated the PAX3/FOXO1 fusion gene status was derived from 287 patients with RMS and evaluated. RESULTS: We showed that our prognostic gene-expression signature and the one previously published performed well with reproducible and significant effects. However, their effect was reduced when cross validated or tested in independent data and did not add new prognostic information over the fusion gene status, which is simpler to assay. Among nonmetastatic patients, patients who were PAX3/FOXO1 positive had a significantly poorer outcome compared with both alveolar-negative and PAX7/FOXO1-positive patients. Furthermore, a new clinicomolecular risk score that incorporated fusion gene status (negative and PAX3/FOXO1 and PAX7/FOXO1 positive), Intergroup Rhabdomyosarcoma Study TNM stage, and age showed a significant increase in performance over the current risk-stratification scheme. CONCLUSION: Gene signatures can improve current stratification of patients with RMS but will require complex assays to be developed and extensive validation before clinical application. A significant majority of their prognostic value was encapsulated by the fusion gene status. A continuous risk score derived from the combination of clinical parameters with the presence or absence of PAX3/FOXO1 represents a robust approach to improving current risk-adapted therapy for RMS.

Rapid and accurate determination of MYCN copy number and 1p deletion in neuroblastoma by quantitative PCR.

MYCN amplification and 1p36 deletion are adverse prognostic factors in neuroblastoma, and rapid accurate determination of MYCN amplification is essential for risk stratification. MYCN copy number and 1p36 deletion status were determined by fluorescence in situ hybridization (FISH) and real time PCR in a diagnostic pathology laboratory setting on 35 consecutive patients with neuroblastoma. The PCR technique was technically successful in all cases and results were generally available within 24 hr of biopsy. There was no discordance between FISH and PCR results. Real time PCR is a reliable, accurate, and simple technique that can be applied to small neuroblastoma biopsies allowing rapid diagnosis.