Notably, after treatment with PC7A NPs and cGAMP–PC7A NPs, CD45+ myeloid cell populations in the tumour showed a higher level of STING activation compared with CD45− cells (Fig. 6e,f), indicating that leukocytes, rather than cancer cells, are the primary targets for STING-mediated immunomodulation by NPs. This evidence concerns the gene PTPRC and cancer.