STING1 and breast cancer: Specifically, for the HER2‐positive subtype of BC, trastuzumab resistance and poor prognosis are highly correlated with insufficient STING activation and the expression of the downstream antitumor cytokine CXCL10/11, which are affected by the downregulation of IFI16 (interferon‐gamma inducible protein 16, a cytoplasmic DNA sensor triggering the STING cascade) [45, 47].