Our ChIP‐seq and cDNA microarray analyses indicated that ectopic NKX2‐1 bound to the locus of PD‐L1/PD‐L2 (Fig 4A and Appendix Fig S1) and induced the expression of PD‐L1 and PD‐L2 in mucus‐producing A549 human lung carcinoma cells (Fig 4B; Maeda et al, 2012), which was also confirmed at the protein level in A549 cells and other mucus‐producing lung cancer cell lines (Fig 4C and D). This evidence concerns the gene PDCD1LG2 and lung cancer.