Host stimulator of interferon genes is essential for the efficacy of anti‐programmed cell death protein 1 inhibitors in non‐small cell lung cancer

The stimulator of interferon genes (STING) pathway is important for anticancer immune responses. However, the relative contributions of host and tumour STING in anti‐programmed cell death protein 1 (anti‐PD‐1) inhibitor responses in non‐small cell lung cancer (NSCLC) are unknown. STING expression in tumour and blood was associated with anti‐PD‐1 therapy in NSCLC patients; Moreover, loss of PD‐1 inhibitor therapeutic potency was demonstrated in STING KO (knock out) splenocytes and STING KO mice. STING knock‐down in tumour cells had no effect. STING on CD8+ T cells and host cells, not tumour cells, correlated with clinical effect of anti‐PD‐1 therapy in NSCLC patients. Finally, adoptive transfer of CD8+ T cells restored PD‐1 inhibitor anticancer effects. STING in host cells but not in tumour cells mediates anti‐PD‐1 inhibitor responses in cancer immunotherapy and could be used to select advantageous NSCLC patients from immunotherapy.