CGAS and neoplasm: Another report noted that directed radiotherapy increases MHC class I expression on tumor cells, leading to increased sensitivity to antigen-specific CTLs and an immune-mediated abscopal effect.14 Recently, the adaptor protein STING (stimulator of interferon genes) has garnered considerable interest given its roles in sensing DNA through cGAS (cyclic GMP-AMP synthase) in DCs in response to locally irradiated tumor cells and activating the STING pathway.15,18 However, it remains unknown why irradiation can trigger the activation of the STING pathway.