EGFR and metastatic malignant neoplasm: In this regard, responsiveness of non-small-cell lung cancers to EGFR TKI is strongly related to epithelial phenotype25, 26, 27 and acquired resistance to EGFR TKI has been associated with epithelial-to-mesenchymal transition (EMT), a critical feature of invasive and metastatic cancers that is associated with poor prognosis in lung cancer.26, 28, 29, 30