VEGFA and glioblastoma: Recently, several genetic biomarkers, such as O(6)‐methylguanine‐DNA methyltransferase (MGMT) methylation, epidermal growth factor receptor variant III (EGFRvIII), vascular endothelial growth factor (VEGF) and isocitrate dehydrogenase (IDH), have been well‐established in GBM.31