When miR-200b or −200c pre-miRs were co-transfected into murine (344SQ) or human (H157 or H1299) lung cancer cells after transfection of wild-type (WT) PD-L1 3′-UTR reporter construct, luciferase reporter activity was inhibited, proving that the miR-200 family members directly regulate PD-L1. The gene discussed is CD274; the disease is lung cancer.