PLK1 and non-small cell lung carcinoma: To confirm the levels of PLK1 in TGF-β-induced EMT, we treated normal lung fibroblast MRC5 cells, primary NSCLC A549 cells, and metastatic NSCLC (NCI-H460 and NCI-H1299 cells) with 2.5 ng/ml of TGF-β.