MAPK3 and central nervous system cancer: ROS can also activate ERK1/2 signaling in glioma.108 RAS, an upstream activator of the ERK1/2 pathway, is also activated through oxidative modification by ROS at its cysteine 118 residue, which leads to inhibition of GTP/GDP exchange.109 Moreover, ROS can modulate pro-apoptotic factors such as Bax,110 Bad, Bim, and FOXO family transcription factors.111 Tumor necrosis factor (TNF) and neuronal growth factor (NGF) display various functions from cell growth and differentiation to cell death.