Glioblastoma (GBM)
The current World Health Organization (WHO) classification divides GBM
tumors into three groups depending on the status of the isocitrate
dehydrogenase (IDH ) gene: IDH wild-type (IDHwt) GBM,
mutated IDH , or not specified GBM (NOS, unevaluated status).
IDHwt GBMs represent around 90% of cases and typically appear in older
patients, whereas around 10% of patients present tumors with anIDH mutation, which correspond to secondary GBMs which originate
from lower grade gliomas, occur in younger patients, and have a better
prognosis. Furthermore, GBMs are defined by other genetic biomarkers,
including O6-methylguanine DNA methyltransferase (MGMT ) promoter
methylation, chromosome 1p/19q deletion, mutations of telomerase reverse
transcriptase (TERT ) promoter, tumor protein P53 (TP53 ),
and phosphatase and tensin homolog (PTEN ), and amplification of
epidermal growth factor receptor (EGFR ) and platelet-derived
growth factor receptor A (PDGFRA ). The prognosis for patients
with GBM is dismal; current treatment, based on combining surgical
resection, radiotherapy and adjuvant chemotherapy still results in a
median overall survival of less than 2 years [11-15].