STING1 and melanoma: However, cGAS-STING is commonly down-regulated in many cancers, as demonstrated in the Cancer Cell Line Encyclopedia (CCLE) dataset, with approximately 35% of all cancer cell lines expressing low levels (<1 TPM) of cGAS and/or STING [20] (Figure 2A) and reported to be commonly inactivated in melanoma and other cancers [17,21].