CD274 and cancer: In the present study, we demonstrated that PD-L1 expression was higher in gastric cancer cell lines with higher pEGFR and pHER2 expressions compared with those with lower pEGFR and pHER2 expressions, and inhibition of the HER2/EGFR pathway decreased PD-L1 expression as well as cytokines release in HER2-amplified cancer cell lines.