HIF1A and glioma: Moreover, other mediators like the expression of TKTL1 (Transketolase-like 1, an enzyme of pentose phosphate pathway) in head and neck carcinomas and gliomas leads to metabolic switch by stabilizing HIF1α for improving energy yield from glucose via glycolysis and enhancing antioxidant defence against ROS via pentose phosphate pathway [32,33].