CD274 and small cell lung carcinoma: demonstrated that targeting DDR proteins with poly ADP-ribose polymerase (PARP) or checkpoint kinase 1 significantly increases the expression of PD-L1, remarkably potentiated the anti-tumor effect of PD-L1 blockade and augmented cytotoxic T-cell infiltration in SCLC mouse models with the activation of STING/TBK1/IRF3 innate immune pathway (173).