KLF4 has been widely reported as an oncogene in multiple cancer types (Rowland and Peeper, 2006; Hu et al., 2015; Hsieh et al., 2017; Murgai et al., 2017), including lung cancer (Yu et al., 2016), ovarian cancer (Zhang et al., 2019), esophageal squamous cell cancer (Tetreault et al., 2010), gastric cancer (Li et al., 2012), colorectal cancer (Li et al., 2011; Gamper et al., 2012), and leukemia (Faber et al., 2013; Li et al., 2015; Seipel et al., 2016; Park et al., 2019). This evidence concerns the gene KLF4 and lung cancer.