Finally, the protein levels of cell proliferation-related protein Ki-67 and cell migration-related protein MMP-9 were inhibited, while cell apoptosis-related protein Cleaved-casp9 was upregulated in NSCLC cells transfected with si-circ_0020123-1 or si-circ_0020123-2 (Fig. 2e). The gene discussed is MMP9; the disease is non-small cell lung carcinoma.