, ASSET (FP7-HEALTH-2010-259348), and EEC (HEALTH-F2-2013-602856) projects, the Société Française des Cancers de l'Enfant and the following associations, the European PROVABES (ERA-649 NET TRANSCAN JTC-2011), pp.14-237

E. Bagouzamanon, L. Santé, and . Amis-de-claire, John Maris for providing genotype information for the neuroblastoma dataset as well as Dr. Liming Liang and Dr. William Cookson for providing access to genotype data of the LCL dataset. The authors also thank the following clinicians and pathologists for providing samples used in this work

R. Bouvier, . Bouvier, E. Brugi-res, J. Cassagnau, C. Champigneulle et al.,

N. Coindre, A. Corradini, A. Coulomb-lhermine, G. Muret, A. S. De-pinieux et al.,

A. Glorion, .. M. Gomez-brouchet, H. Guinebreti-re, C. Jouan, B. Jeanne-pasquier et al.,

C. Pierga, S. Piguet, E. Piperno-neumann, D. Plouvier, J. Ranchere-vince et al.,

O. Delattre, Gene fusion with an ETS DNA-binding domain caused by chromosome translocation in human tumours, Nature, vol.359, pp.162-165, 1992.

K. Gangwal, Microsatellites as EWS/FLI response elements in Ewing's sarcoma, Proc. Natl. Acad. Sci. U. S. A, vol.105, pp.10149-10154, 2008.

N. Guillon, The oncogenic EWS-FLI1 protein binds in vivo GGAA microsatellite sequences with potential transcriptional activation function, PloS One, vol.4, p.4932, 2009.
URL : https://hal.archives-ouvertes.fr/inserm-02438659

S. Postel-vinay, Common variants near TARDBP and EGR2 are associated with susceptibility to Ewing sarcoma, Nat. Genet, vol.44, pp.323-327, 2012.
URL : https://hal.archives-ouvertes.fr/inserm-02438686

V. Levetzow and C. , Modeling initiation of Ewing sarcoma in human neural crest cells, PloS One, vol.6, p.19305, 2011.

F. Tirode, Mesenchymal stem cell features of Ewing tumors, Cancer Cell, vol.11, pp.421-429, 2007.
URL : https://hal.archives-ouvertes.fr/inserm-02438637

O. Delattre, The Ewing family of tumors--a subgroup of small-round-cell tumors defined by specific chimeric transcripts, N. Engl. J. Med, vol.331, pp.294-299, 1994.

P. H. Sorensen, A second Ewing's sarcoma translocation, t(21;22), fuses the EWS gene to another ETS-family transcription factor, ERG, Nat Genet, vol.6, pp.146-51, 1994.

M. Patel, Tumor-specific retargeting of an oncogenic transcription factor chimera results in dysregulation of chromatin and transcription, Genome Res, vol.22, pp.259-270, 2012.

A. S. Brohl, The genomic landscape of the Ewing Sarcoma family of tumors reveals recurrent STAG2 mutation, PLoS Genet, vol.10, p.1004475, 2014.

B. D. Crompton, The Genomic Landscape of Pediatric Ewing Sarcoma, Cancer Discov, 2014.

F. Tirode, Genomic landscape of Ewing sarcoma defines an aggressive subtype with co-association of STAG2 and TP53 mutations, Cancer Discov, 2014.

J. Worch, Racial differences in the incidence of mesenchymal tumors associated with EWSR1 translocation, Cancer Epidemiol. Biomark. Prev. Publ. Am. Assoc. Cancer Res. Cosponsored Am. Soc. Prev. Oncol, vol.20, pp.449-453, 2011.

J. E. Dominy and . Jr, Discovery and characterization of a second mammalian thiol dioxygenase, cysteamine dioxygenase, J. Biol. Chem, vol.282, pp.25189-25198, 2007.

A. Chandra, S. Lan, J. Zhu, V. A. Siclari, and L. Qin, Epidermal growth factor receptor (EGFR) signaling promotes proliferation and survival in osteoprogenitors by increasing early growth response 2 (EGR2) expression, J. Biol. Chem, vol.288, pp.20488-20498, 2013.

G. S. Maro, Neural crest boundary cap cells constitute a source of neuronal and glial cells of the PNS, Nat. Neurosci, vol.7, pp.930-938, 2004.

S. Schneider-maunoury, Disruption of Krox-20 results in alteration of rhombomeres 3 and 5 in the developing hindbrain, Cell, vol.75, pp.1199-1214, 1993.

P. Topilko, Krox-20 controls myelination in the peripheral nervous system, Nature, vol.371, pp.796-799, 1994.

C. Mackintosh, J. Madoz-gúrpide, J. L. Ordóñez, D. Osuna, and D. Herrero-martín, The molecular pathogenesis of Ewing's sarcoma, Cancer Biol. Ther, vol.9, pp.655-667, 2010.

N. Riggi, EWS-FLI1 Utilizes Divergent Chromatin Remodeling Mechanisms to Directly Activate or Repress Enhancer Elements in Ewing Sarcoma. Cancer Cell 0, 21. ENCODE Project Consortium et al. An integrated encyclopedia of DNA elements in the human genome, Nature, vol.489, pp.57-74, 2012.

J. Ernst, Mapping and analysis of chromatin state dynamics in nine human cell types, Nature, vol.473, pp.43-49, 2011.

M. T. Maurano, Systematic localization of common disease-associated variation in regulatory DNA, Science, vol.337, pp.1190-1195, 2012.

D. Chomette, M. Frain, S. Cereghini, P. Charnay, and J. Ghislain, Krox20 hindbrain cisregulatory landscape: interplay between multiple long-range initiation and autoregulatory elements, Dev. Camb. Engl, vol.133, pp.1253-1262, 2006.
URL : https://hal.archives-ouvertes.fr/hal-02265303

J. Ghislain, Characterisation of cis-acting sequences reveals a biphasic, axondependant regulation of Krox20 during Schwann cell development, Dev. Camb. Engl, vol.129, pp.155-166, 2002.

L. L. Faye, M. J. Machiela, P. Kraft, S. B. Bull, and L. Sun, Re-ranking sequencing variants in the post-GWAS era for accurate causal variant identification, PLoS Genet, vol.9, p.1003609, 2013.

. Genomes-project-consortium, An integrated map of genetic variation from 1,092 human genomes, Nature, vol.491, pp.56-65, 2012.

M. Mendiola, The orphan nuclear receptor DAX1 is up-regulated by the EWS/FLI1 oncoprotein and is highly expressed in Ewing tumors, Int. J. Cancer J. Int. Cancer, vol.118, pp.1381-1389, 2006.
URL : https://hal.archives-ouvertes.fr/hal-00172274

D. Surdez, Targeting the EWSR1-FLI1 oncogene-induced protein kinase PKC-? abolishes ewing sarcoma growth, Cancer Res, vol.72, pp.4494-4503, 2012.
URL : https://hal.archives-ouvertes.fr/inserm-02438737

J. Carrillo, Cholecystokinin down-regulation by RNA interference impairs Ewing tumor growth, Clin. Cancer Res. Off. J. Am. Assoc. Cancer Res, vol.13, pp.2429-2440, 2007.