TOP2A and non-small cell lung carcinoma: The regulatory effect of TOP2A on the proliferation ability of NSCLC cells was further confirmed by colony formation assays, which showed that knockdown of TOP2A gene significantly inhibited the clonogenic ability of NSCLC cells (Fig. 4E,G), while the clonogenic ability of NSCLC cells overexpressing TOP2A was significantly enhanced (Fig. 4F,H).