Furthermore, the expression levels of epithelial-mesenchymal transition (EMT) associated proteins (N-cadherin and Vimentin) were determined (Fig. 7c-f), and the results showed that knock-down of circ-CPA4 inhibited the expressions of N-cadherin and Vimentin, which were also increased by knocking down let-7 miRNA and upregulating PD-L1 in A549 and H1299 cells (Fig. 7c-f), indicating that circ-CPA4 regulated NSCLC cell mobility and EMT by targeting let-7 miRNA/PD-L1 axis. The gene discussed is CD274; the disease is non-small cell lung carcinoma.