PLK1 and non-small cell lung carcinoma: To confirm whether the observed decrease in cell proliferation in NSCLC cells following treatment with PLK1 siRNA was associated with increased cell death and/or cell cycle arrest, we treated 2 different NSCLC cell lines (H1299 and H460) with PLK1 siRNA complexed to Lipofectamine 2000 (L2K), and measured apoptosis by annexin V staining and flow cytometry.