Genetics of adult glioma.

Gliomas make up approximately 30% of all brain and central nervous system tumors and 80% of all malignant brain tumors. Despite the frequency of gliomas, the etiology of these tumors remains largely unknown. Diffuse gliomas, including astrocytomas and oligodendrogliomas, belong to a single pathologic class but have very different histologies and molecular etiologies. Recent genomic studies have identified separate molecular subtypes within the glioma classification that appear to correlate with biological etiology, prognosis, and response to therapy. The discovery of these subtypes suggests that molecular genetic tests are and will be useful, beyond classical histology, for the clinical classification of gliomas. While a familial susceptibility to glioma has been identified, only a small percentage of gliomas are thought to be due to single-gene hereditary cancer syndromes. Through the use of linkage studies and genome-wide association studies, multiple germline variants have been identified that are beginning to define the genetic susceptibility to glioma.