MAPK3 and lung cancer: Our previous study showed that ERK1/2 can activate ZEB1 and VIM to increase metastasis in lung cancer cells.[36] In this study, we added a MEK inhibitor to co‐cultured 231‐GFP cells and found that the levels of ZEB1 and VIM were greatly reduced (Figure S8F, Supporting Information), which suggested that ERK1/2 acts upstream of ZEB1 and VIM.