COX4I2 and central nervous system cancer: Additionally, using an in vitro model of GBM adaptive radioresistance, we found that exposure of glioma cells to fractionated radiation promotes a switch from the expression of the COX4-2 isoform to the COX4-1 isoform, which, in turn, promotes the assembly of mitochondrial supercomplexes that enhance OXPHOS while minimizing ROS production [5].