Brain tumor
Glioblastoma multiforme (GBM) is the most aggressive (grade IV) and most common form of a malignant brain tumor. Even when aggressive multimodality therapy consisting of radiotherapy, chemotherapy, and surgical excision is used, median survival is only 12–17 months. Standard therapy for glioblastoma multiforme consists of maximal surgical resection of the tumor, followed by radiotherapy between two and four weeks after the surgical procedure to remove the cancer, then by chemotherapy, such as temozolomide. Most patients with glioblastoma take a corticosteroid, typically dexamethasone, during their illness to relieve symptoms. Experimental treatments include targeted therapy, gamma knife radiosurgery, boron neutron capture therapy and gene therapy.
Glioma
Germ-line (inherited) polymorphisms of the DNA repair genes "ERCC1", "ERCC2" ("XPD") and "XRCC1" increase the risk of glioma. This indicates that altered or deficient repair of DNA damage contributes to the formation of gliomas. DNA damages are a likely major primary cause of progression to cancer in general. Excess DNA damages can give rise to mutations through translesion synthesis. Furthermore, incomplete DNA repair can give rise to epigenetic alterations or epimutations. Such mutations and epimutations may provide a cell with a proliferative advantage which can then, by a process of natural selection, lead to progression to cancer.