Glial Malignancies

Gliomas comprise a diverse spectrum of related tumor subtypes with varying biological and molecular features and clinical outcomes. Advances in detailed genetic and epigenetic characterizations along with an appreciation that subtypes associated with developmental origins, including brain location and patient age, have shifted glioma classification from the historical reliance on histopathological features to updated categories incorporating molecular signatures and spatiotemporal incidence. Within a subtype, individual gliomas show cellular heterogeneity, generally containing subpopulations resembling different types of normal glial and progenitor cells. In addition to tumor-autonomous mechanisms of aberrant growth regulation driven by genetic mutations and signaling between tumor cells, interactions with the tumor microenvironment, including neurons, astrocytes, oligodendrocyte precursor cells, and the immune microenvironment play important roles in driving glioma growth and influencing response to treatment. The emerging understanding of the complex contributions of normal brain to glioma growth represents new opportunities for therapeutic advances.