CGAS and cancer: It was previously assumed that chemotherapy drugs act directly on cancer cells to induce cell death; however, some studies observed the activation of antitumor immunity after chemotherapy.98,99 A later study then concluded that increased cell death by chemotherapy releases danger-associated molecules that can activate the immune system.100 More recent studies are now suggesting that chemotherapy drugs may also have direct immunostimulatory effects through activating cGAS in cancer cells (Fig. 2c).