NTRK1 and glioblastoma: The complex pathogenesis in GBM involves receptor tyrosine kinase (RTK) signaling through two main downstream signaling pathways, Ras/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and Ras/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) [3].