Ki-67 immunohistochemical staining assay showed that the Ki-67 expression was significantly downregulated by overexpressing hsa_circ_0003176 (Figures 3(e) and 3(f)), suggesting that overexpression of hsa_circ_0003176 inhibited NSCLC cell proliferation. This evidence concerns the gene MKI67 and non-small cell lung carcinoma.