Recently, durable regression of irradiated tumors and abscopal responses observed in mammary tumor-bearing mouse models treated with combination RT and checkpoint blockade were shown to be dependent on cancer cell-intrinsic activation of the type I IFN pathway as mediated by cyclic GMP-AMP (cGAMP) synthase (cGAS) and stimulator of interferon genes (STING) signaling [89]. This evidence concerns the gene STING1 and breast cancer.