CGAS and cancer: When radiation is delivered at high dose in a single fraction, with a threshold that varies between 12 and 18 Gy in different cancer cells, Trex1 is induced at levels sufficient to degrade the DNA that accumulates in the cytosol of irradiated cancer cells precluding activation of the type-I interferon (IFN-I) pathway mediated via cyclic GMP-AMP (cGAMP) synthase (cGAS) and its downstream adaptor stimulator of interferon genes (STING)11.