• Agustí Alentorn, Hinke F van Thuijl, Yannick Marie, Hussa Alshehhi, Catherine Carpentier, Blandine Boisselier, Florence Laigle-Donadey, Karima Mokhtari, Ilari Scheinin, Pieter Wesseling, Bauke Ylstra, Laurent Capelle, Khê Hoang-Xuan, Marc Sanson, Jean-Yves Delattre, Jaap C Reijneveld, and Ahmed Idbaih.
• Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière (CRICM), UMRS 975, Inserm U 975, CNRS, UMR 7225, Université Pierre et Marie Curie, Paris, France (A.A., Y.M, C.C., B.B., K.M., K.H.-X., M.S., J.-Y.D., A.I.); Department of Neuropathology (H.A., K.M.); Department of Neurology 2-Mazarin (F.L.-D., K.H.-X., M.S., J.-Y.D., A.I.); Department of Neurosurgery, AP-HP, Groupe Hospitalier Pitié-Salpêtriére, Paris, France (L.C.); Department of Neurology (H.F.v.T., J.C.R.); Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands (I.S., P.W., B.Y.); Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands (P.W.).
• Neuro-oncology. 2014 Mar 1;16(3):400-8.

BackgroundDiffuse low-grade gliomas (LGGs) form a heterogeneous subgroup of gliomas in adults. Chromosome (chr) arms 1p/19q codeletion and IDH mutation have been shown to be closely associated with oligodendroglial phenotype and better prognosis. We sought to identify relevant biomarkers in non 1p/19q codeleted LGGs.MethodsWe characterized a retrospective series of 126 LGGs using genomic arrays, microsatellite analysis, IDH sequencing, MGMT promoter methylation assay, and p53 expression analysis.ResultsOur study confirms that 1p/19q codeletion, mutually exclusive with p53 overexpression, was associated with: (i) better prognosis, (ii) oligodendroglial phenotype, (iii) MGMT promoter methylation, and (iv) IDH mutation. Interestingly, 1p/19q codeleted tumors occur in older patients at diagnosis. Our study shows that non 1p/19q codeleted LGGs can be divided in 5 main genomic subgroups: (i) 11p loss, (ii) 19q loss (iii) 7 gain, (iv) 19 gain, and (v) unclassified. In non 1p/19q codeleted LGGs, we demonstrated that (i) 11p loss is associated with astrocytoma phenotype and has an independent negative prognostic value, and (ii) 19q loss diminished the favorable prognostic value of IDH mutation. Our findings were validated in an independent cohort of 98 LGGs.ConclusionNovel genomic entities and biomarkers have been identified in non 1p/19q codeleted LGGs. Our findings may help to stratify non 1p/19q codeleted LGGs, facilitating future individualization of treatment. Further prospective studies are warranted to support our findings.

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