Primary brain tumors comprise a large group of malignant and non-malignant tumors including heterogeneous entities with various biological and clinical behaviors. Up till recently, diagnosis of brain cancers, that drives treatment decision-making, was based on integration of clinical, radiological and pathological features of patients and tumors. Over the last years, practical neuro-oncology has entered an era of molecular-based personalized medicine. Indeed, molecular features of tumors provide critical information to physicians for daily clinical management of patients and for design of relevant clinical research. Sporadic gliomas or glial tumors are the most common primary brain tumors in adults. Recently, their medical management has been revolutionized by molecular data. Indeed, optimal therapeutic management of grade III glioma patients now requires assessment of chromosome arms 1p/19q copy number and IDH mutational statuses as predictive and prognostic biomarkers. Indeed, two large phase III clinical trials have demonstrated that early chemotherapy plus radiotherapy, versus radiotherapy alone, doubles median overall survival of patients suffering from 1p/19q co-deleted and/or IDH mutated anaplastic oligodendroglial tumor. Interestingly, both biomarkers have been identified in a large proportion of WHO grade II gliomas. Their clinical value, in this population, is under investigation through multiple phase III clinical trials. In sporadic WHO grade I gliomas, and specifically in pilocytic astrocytomas, MAPK signaling pathway activation is a frequent event, mainly due to genetic alterations involving BRAF gene. This characteristic opens new therapeutic perspectives using MAPK signaling pathway inhibitors. Finally, in the most aggressive gliomas, WHO grade IV gliomas, two critical biomarkers have been identified: (i) MGMT promoter methylation associated with longer survival and better response to chemotherapy and (ii) IDH mutations predicting better prognosis. Although, further studies are needed, MGMT promoter methylation will undoubtedly be transferred soon to clinical practice. Molecular characteristics are beginning to be valuable and indispensable in neuro-oncology for better management of brain tumors patients. The near future will be marked by identification of novel molecular biomarkers and their validation for clinical practice.

Jusqu’à tout récemment, le diagnostic des tumeurs cérébrales, pivot de la prise en charge thérapeutique, était basé sur les caractéristiques clinico-radiologiques et neuropathologiques du patient et de sa tumeur. Ces dernières années, la neuro-oncologie clinique est entrée dans l’ère de la médecine personnalisée moléculaire. En effet, les caractéristiques moléculaires de la tumeur apportent des informations majeures au clinicien pour le traitement du patient. Les gliomes sont les tumeurs cérébrales primitives les plus fréquentes chez l’adulte. Leur prise en charge médicale a été transformée, depuis peu, par les données moléculaires. À titre d’exemple, le traitement optimal des patients souffrant d’un gliome de grade III nécessite désormais la détermination des statuts des chromosomes 1p et 19q et des gènes IDH. En effet, deux essais cliniques de phase III ont démontré que la chimiothérapie précoce plus la radiothérapie, versus la radiothérapie seule, double la survie globale médiane des patients souffrant d’un gliome grade III 1p/19q co-délété et/ou IDH muté. Les données moléculaires sont dorénavant indispensables en neuro-oncologie pour une prise en charge médicale optimale des patients. Les prochaines années seront incontestablement marquées, dans tous les sous-types de tumeurs cérébrales, par l’identification et la validation de nouveaux biomarqueurs moléculaires pertinents pour la pratique clinique.