KLF4 and lung cancer: The expression of several genes involved in these gene sets were confirmed by quantitative RT-PCR, and the results revealed that the knockdown of PD-L1 in A549 cells reduced the expression of EZH2, JAG1, IGFBP3, CAV, TGFB2, WEE1, TYMS, KLF4, and CDC25A but increased the expression of PDCD4 and GPX3, two potential tumor suppressors in lung cancers [26,27] (Figure 5C).