CPA4 and non-small cell lung carcinoma: The results showed that expression levels of circ-CPA4 (Fig. 1l) and PD-L1 (Fig. 1n, Fig. 1o, p) were higher, and let-7 miRNA (Fig. 1m) was lower in NSCLC cell lines compared to the HBE cells, which were in accordance with our clinical results.