Neuroblastoma is the most common cancer in infants younger than 12 months of age, occurring with an incidence of 1 in 100,000 children. The clinical outcome of neuroblastoma ranges from spontaneous regression to treatment-resistant progression and/or metastasis, and accounts for 8–10% of childhood cancer deaths. Segmental chromosomal aberrations, as well as MYCN and ALK amplification, are among factors contributing to an unfavorable genomic profile and high-risk disease classification. Here, we describe a 5-year-old male who presented with a large right renal neuroblastoma tumor having lung and liver metastases. Fluorescence in situ hybridization analysis indicated the presence of >20 copies of the 5′ region of the ALK gene in 26% of cells examined. Subsequent copy number assessment did not confirm ALK amplification, but revealed a gain of exons 2–5 of ALK, consistent with increased copy number for the 5′ region of the ALK gene. Subsequent array analysis showed the presence of other unfavorable prognostic genomic features, including segmental gain of the 17q region and amplification of the long arm of chromosome 12 harboring CDK4 and MDM2, both reported to be poor prognostic indicators in patients with atypical clinical features in neuroblastoma. Taken together, this report illustrates the importance of careful interpretation of aberrant FISH findings and subsequent use of orthogonal methods to clarify the presence of genomic alterations to successfully determine potential treatment targets.

Abstract INTRODUCTION CNS tumors are the second most common neoplasm in children and have historically been associated with longer time to diagnosis. Data on the time-to-diagnosis for Canadian children with CNS tumors are limited and outdated. We aimed at evaluating the diagnostic interval time(DIT) for Canadian children, and identifying factors possibly associated with prolonged DIT. METHODS Using the CYP-C database, we analyzed data from children <15 years, diagnosed with CNS tumors between 2001–2015. DIT was defined as time in weeks, elapsed from the first contact with a healthcare provider to confirming diagnosis. We described DIT according to patient’s demographics, socioeconomic, geographic factors as well as tumor-related criteria. RESULTS Patients from all Canadian provinces, except Ontario, had available timepoints to calculate DIT. The cohort included 842 patients. Mean DIT for all patients was 11.7 weeks(median 1.4). Gliomas had the longest mean DIT and embryonal tumors had the shortest(14.6 and 3.6 weeks p<0.01). ATRT and medulloblastoma had a mean DIT of 1.3 and 4.3 weeks respectively. DIT for HGG was shorter than for LGG (6.4 versus 16.1 weeks, p<0.01). Metastatic disease, infratentorial tumors, or age £36 months had significantly shorter DIT (5.6 vs 12.4 vs 18.4, 7.4 vs 13.1 and 8.6). Sex, annual income(QAIPPE), and distance from tertiary center did not influence DIT. CONCLUSION The current diagnostic interval time for pediatric CNS tumors in Canada is 11.7 weeks(median 1.4weeks). These results only reflect the healthcare system’s contribution toward diagnosis confirmation, but not the patient interval before seeking medical attention.

BACKGROUND:Mutations of the isocitrate dehydrogenase 1 and 2 gene (IDH1/2) were initially thought to enhance cancer cell survival and proliferation by promoting the Warburg effect. However, recent experimental data have shown that production of 2-hydroxyglutarate by IDH mutant cells promotes hypoxia-inducible factor (HIF)1α degradation and, by doing so, may have unexpected metabolic effects.METHODS:We used human glioma tissues and derived brain tumor stem cells (BTSCs) to study the expression of HIF1α target genes in IDH mutant ((mt)) and IDH wild-type ((wt)) tumors. Focusing thereafter on the major glycolytic enzyme, lactate dehydrogenase A (LDHA), we used standard molecular methods and pyrosequencing-based DNA methylation analysis to identify mechanisms by which LDHA expression was regulated in human gliomas.RESULTS:We found that HIF1α-responsive genes, including many essential for glycolysis (SLC2A1, PDK1, LDHA, SLC16A3), were underexpressed in IDH(mt) gliomas and/or derived BTSCs. We then demonstrated that LDHA was silenced in IDH(mt) derived BTSCs, including those that did not retain the mutant IDH1 allele (mIDH(wt)), matched BTSC xenografts, and parental glioma tissues. Silencing of LDHA was associated with increased methylation of the LDHA promoter, as was ectopic expression of mutant IDH1 in immortalized human astrocytes. Furthermore, in a search of The Cancer Genome Atlas, we found low expression and high methylation of LDHA in IDH(mt) glioblastomas.CONCLUSION:To our knowledge, this is the first demonstration of downregulation of LDHA in cancer. Although unexpected findings, silencing of LDHA and downregulation of several other glycolysis essential genes raise the intriguing possibility that IDH(mt) gliomas have limited glycolytic capacity, which may contribute to their slow growth and better prognosis.

Oligodendroglioma is characterized by mutations of IDH and CIC, 1p/19q loss, and slow growth. We found that NHE‐1 on 1p is silenced in oligodendrogliomas secondary to IDH‐associated hypermethylation and 1p allelic loss. Silencing lowers intracellular pH and attenuates acid load recovery in oligodendroglioma cells. Others have shown that rapid tumor growth cannot occur without NHE‐1–mediated neutralization of the acidosis generated by the Warburg glycolytic shift. Our findings show for the first time that the pH regulator NHE‐1 can be silenced in a human cancer and also suggest that pH deregulation may contribute to the distinctive biology of human oligodendroglioma. Ann Neurol 2012;71:845–849

Glioblastoma development should be subdivided in three phases, one prehypoxic and two post-hypoxic phases.The pre-hypoxic phase, ranging from 10% to 5% oxygen (normal brain oxygen levels), should be characterized only by CD133-cells, and these cells are inevitably also those that first conquer and microinfiltrate the brain parenchyma.In some areas of the bulk, the oxygen concentration falls to about 5% or less, and hypoxia develops.The second phase ranges from about 5% to about 1% oxygen concentration.This phase of mild and severe hypoxia is regulated by the epigenetic shift driven by HIF2a, which is expressed only in cancer stem cells (CSCs) and is correlated with CD133 expression.When oxygen levels fall in certain regions of the tumor to about 1% or less, the third phase of very severe hypoxia begins.This phase is driven by HIF1a, which is expressed both by CSCs and committed cells.To date, the only way to monitor the development of the growing tumor in animal model is imaging.However, in order to reproduce what really happens in a human patient affected by a glioblastoma, we need a model that allows cells, biopsies, and sections to be obtained throughout tumor development.I recently proposed an original animal model that can enable us to study and monitor the entire development of the glioblastoma in only one generation of mice.The model allows the creation of a pool of twin transplanted animals in the same condition and the study of glioblastoma development, both in the bulk and in the brain parenchyma.This is done by taking multiple biopsies and by performing multiple stainings on sections.Through parenchymal biopsies and stainings on sections, we have four means to identify the CSCs microinfiltrated in the brain with the possibility of targeting them.TM-02.