MAPK3 and non-small cell lung carcinoma: In addition to A549 cell line, the positive correlation was also observed in NSCLC tissues, in which invading tumor cells were strongly stained for phospho-ERK1/2 and weakly stained for E-cadherin, indicating that the mechanical relation between E-cadherin and ERK in an A549 model cell line is relevant in NSCLC, demonstrating the importance of aberrant ERK activation in the invading tumor cells with EMT phenotypes.