CGAS and cancer: To analyse if cGAS activity contributes to the dysfunction of STING in cGAMP unresponsive cancer cells, we inhibited cGAS expression by cGAS-specific siRNAs in DU145 and TRAMP-C2 cells or by a cGAS-specific RNA-guided Cas9 nuclease in A549, HeLa, and HCT116 cells27.