To study the potential effect of the mutated-EGFRs on lung cancer progression, mutated EGFR [L858R (a point mutation in exon 21) or Del 3 (an in-frame deletion in exon 19)] or the wild-type (WT) one was introduced into H1437 (non-mutated) lung adenocarcinoma cells via lentiviral infection (Figure 3A). The ectopic expression of mutated- but not WT-EGFRs induced a morphological change from an epithelial phenotype to a spindle-like morphology (Figure 3B and Supplementary Figure 1A). Additionally, the electric cell-substrate impedance sensing (ECIS) analysis revealed that the mutated-EGFRs attenuated the impedance, indicating that the mutated-EGFRs inhibit barrier properties in lung cancer cells (Figure 3C). A wound healing assay showed that the mutated-EGFRs promoted cell migration, compared to the WT-EGFR (Figure 3D and Supplementary Figure 1B). In support of this notion, the cell-tracking assay showed that migration of H1437 cells were promoted by mutated-EGFRs but not the wild-type one (Figure 3E). Moreover, an endothelial cell-based invasion analysis was adopted to examine the metastatic potential of mutated-EGFR cells. We observed that H1437 cells carrying the mutated-EGFRs invaded more profoundly into the endothelial cells, thus attenuating the impedance of endothelial cells as compared to their wild-type counterparts (Figure 3F). Immunoblotting showed that the mutated-EGFRs not only elevated the levels of phosphorylated EGFR but also increased vimentin expression (Figure 3A), a hallmark of mesenchymal cells. To validate whether the mutated-EGFR promotes vimentin expression, we further conducted immunohistochemistry (IHC) staining on clinical tumor samples. Correlation analysis revealed that the EGFR-mutation status is associated with vimentin expression as compared to WT-EGFR (75.3% vs. 51.2%, P = 0.007) (Figure 3G). This finding was further supported by the analysis of two different lung adenocarcinoma cohorts (Figure 3H) (The raw materials were download from publicly accessible datasets) [14–15]. These data indicate that the mutated-EGFR promotes lung cancer cell dissemination and correlates with vimentin expression.