STING1 and neoplasm: In response to cytosolic DNA shed by tumor cells, 2′3′-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), a secondary messenger in eukaryotic cells and an endogenous ligand for STING, is produced to bind STING and trigger the activation of the STING signaling pathway that leads to the upregulation of type I interferon, a key prerequisite for the maturation of dendritic cells in the tumor microenvironment and the ensuing anti-tumor immune responses.