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Cho Y.-J.,Childrens Hospital Boston | Cho Y.-J.,Harvard University | Cho Y.-J.,Brigham and Women's Hospital | Cho Y.-J.,Dana-Farber Cancer Institute | And 196 more authors.
Journal of Clinical Oncology | Year: 2011

Purpose Medulloblastomas are heterogeneous tumors that collectively represent the most common malignant brain tumor in children. To understand the molecular characteristics underlying their heterogeneity and to identify whether such characteristics represent risk factors for patients with this disease, we performed an integrated genomic analysis of a large series of primary tumors. Patients and Methods We profiled the mRNA transcriptome of 194 medulloblastomas and performed high-density single nucleotide polymorphism array and miRNA analysis on 115 and 98 of these, respectively. Non-negative matrix factorization-based clustering of mRNA expression data was used to identify molecular subgroups of medulloblastoma; DNA copy number, miRNA profiles, and clinical outcomes were analyzed for each. We additionally validated our findings in three previously published independent medulloblastoma data sets. Results Identified are six molecular subgroups of medulloblastoma, each with a unique combination of numerical and structural chromosomal aberrations that globally influence mRNA and miRNA expression. Wereveal the relative contribution of each subgroup to clinical outcome as a whole and show that a previously unidentified molecular subgroup, characterized genetically by c-MYC copy number gains and transcriptionally by enrichment of photoreceptor pathways and increased miR-183̃96̃182 expression, is associated with significantly lower rates of event-free and overall survivals. Conclusion Our results detail the complex genomic heterogeneity of medulloblastomas and identify a previously unrecognized molecular subgroup with poor clinical outcome for which more effective therapeutic strategies should be developed. © 2011 by American Society of Clinical Oncology.


Bielle F.,APHP | Freneaux P.,Laboratoire dAnatomie Pathologique | Jeanne-Pasquier C.,Service dAnatomie Pathologique | Maran-Gonzalez A.,Service dAnatomie Pathologique | And 12 more authors.
American Journal of Surgical Pathology | Year: 2012

Peripheral neuroblastic tumors are the most commonly occurring extracranial tumors in children. Although a reliable diagnosis is achievable in the majority of cases, diagnosis of a minority of peripheral neuroblastic tumor cases (especially undifferentiated neuroblastoma) poses a challenge compared with that of other pediatric small round blue-cell tumors. A panel of immunohistochemical markers and fusion transcripts is available for the diagnosis of such tumors, but the markers for neuroblastoma lack specificity and sensitivity. As the transcription factor PHOX2B is highly specific for the peripheral autonomic nervous system from which peripheral neuroblastic tumors are derived, we have assessed PHOX2B immunolabeling as a diagnostic tool in pediatric small round blue-cell tumors. We observed PHOX2B expression in all peripheral neuroblastic tumors, paragangliomas, and pheochromocytomas tested but in no other pediatric tumors among the 388 cases studied by expression microarray and the 109 cases studied by immunohistochemical analysis. We then assessed the results of PHOX2B immunohistochemistry in 12 cases of undifferentiated pediatric neoplasms: PHOX2B was expressed in 6/6 undifferentiated neuroblastomas and in no other small round blue-cell tumors. Finally, we showed that PHOX2B immunohistochemical analysis improves the diagnosis of undifferentiated neuroblastoma with high specificity and sensitivity. © 2012 by Lippincott Williams & Wilkins.

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