The EGFR-MEK-ERK1/2 pathway has been implicated in the transcriptional regulation of CLDN2 in A549 lung adenocarcinoma cells through binding of the transcription factors, c-Fos and c-Jun, to the human CLDN2 promoter region via an AP-1 binding site [28]. This evidence concerns the gene MAPK3 and lung adenocarcinoma.