NOX4 and glioblastoma: Two major coordinators of oncogenic metabolic adaptation are the hypoxia inducible factor 1 (HIF-1) and AMP-activated protein kinase (AMPK), and in certain tumor types (e.g., glioblastoma, renal and gastric cell carcinomas) NOX4 has been recognized as a modulator of their signaling [28,29,30,31,32,33,34].