Metabolic reprogramming in the pathogenesis of glioma: Update.

Cancer is a genetic disease that is currently classified not only by its tissue and cell type of origin but increasingly by its molecular composition. Increasingly, tumor classification and subtyping is being performed based upon the oncogene gains, tumor suppressor losses, and associated epigenetic and transcriptional features. However, cancers, including brain tumors, are also characterized by profound alterations in cellular metabolism. At present, even though signature mutations in known metabolic enzymes are recognized as being important, the metabolic landscape of tumors is not currently incorporated into tumor diagnostic categories. Here we describe a set of recent discoveries on metabolic reprogramming driven by mutations in the genes for the isocitrate dehydrogenase (IDH) and receptor tyrosine kinase (RTK) pathways, which are the most commonly observed aberrations in diffuse gliomas. We highlight the importance of oncometabolites to dynamically shift the epigenetic landscape in IDH-mutant gliomas, and c-Myc and mechanistic target of rapamycin (mTOR) complexes in RTK-mutated gliomas to adapt to the microenvironment through metabolic reprogramming. These signify the integration of the genetic mutations with metabolic reprogramming and epigenetic shifts in diffuse gliomas, shedding new light onto potential patient subsets, coupled with information to guide the development of new therapeutic opportunities against the deadly types of brain tumors.