CD274 and lung carcinoma: To further conform the role of PI3K/AKT and Erk-signaling pathway in PD-L1 mediated proliferation in lung cancer cells, LY294002 and U0126 were used to pretreated H1299 and H358 cells, and followed by transfection with PD-L1 overexpression plasmid or PD-L1 specific siRNA.LY294002, significantly inhibited lung cancer cell proliferation, whereas inhibitor pretreatment followed by PD-L1 overexpression or knockdown did not obviously alter the proliferative promotion or inhibition in lung cancer cells, indicating the essential role of PI3K/AKT in lung cancer proliferation (Fig. 4b).