INSR and glioblastoma: Fifty-eight RTKs divided into 20 classes have been detected in humans, and the abnormality of some specific classes, for example, EGFR, insulin receptor (INSR), vascular endothelial growth factor receptor (VEGFR), and fibroblast growth factor receptor (FGFR), is closely related to GBM proliferation, invasion, and drug resistance, leading to a poor prognosis[56].