In addition, the let-7 mimic and inhibitor were successfully delivered into the NSCLC cells (Fig. 3j), and the results showed that overexpressed let-7 miRNA significantly inhibited mRNA levels of PD-L1 in NSCLC cells, which were increased by transfecting cells with let-7 miRNA inhibitor (Fig. 3k). This evidence concerns the gene CD274 and non-small cell lung carcinoma.