Besides, the levels of let-7 miRNA were negatively correlated with circ-CPA4 (Fig. 1f) and PD-L1 mRNA (Fig. 1g), and the levels of circ-CPA4 were positively correlated with PD-L1 mRNA (Fig. 1h) in NSCLC tissues. The gene discussed is CPA4; the disease is non-small cell lung carcinoma.