Liu K, Chen X, Wu L, et al. - To clarify the influence of ID1 expression on osimertinib resistance in EGFR (epidermal growth factor receptor) T790M-positive non-small cell lung cancer (NSCLC), this study was undertaken. A drug-resistant cell line, H1975/OR, was established from the osimertinib-sensitive cell line H1975. Changes in ID1 protein expression and Epithelial–mesenchymal transition (EMT)-related proteins were investigated. In osimertinib-resistant NSCLC cells, there was lower expression level of the EMT-related protein E-cadherin vs that of sensitive cells, while higher expression level of ID1 and vimentin was detected vs those of sensitive cells. In both osimertinib-sensitive and resistant cells, a close association of ID1 expression levels with E-cadherin as well as vimentin was observed. Alteration in the expression of E-cadherin could be brought about by change of ID1 expression in H1975/OR cells. In EGFR T790M-positive NSCLC, mechanism of ID1 mediated resistance to osimertinib via EMT was revealed herein, which may offer new ideas as well as methods for the management of EGFR mutated NSCLC following osimertinib resistance.