In our study, we also observed that FOXF2 expression was frequently at low levels in tumor tissue when compared with its paired non-tumor tissue, which agreed with previous studies in breast cancer, gastric cancer, colorectal cancer, lung cancer and hepatocellular carcinoma (Cai et al., 2015; Higashimori et al., 2018; Zhang et al., 2015; Kundu et al., 2016; Shi et al., 2016). This evidence concerns the gene FOXF2 and lung cancer.