[Non-small Cell Lung Cancer Cell Line PC-9 Drug-resistant Mutant Cell Line 
Establishment and Validation of Their Sensitivity to EGFR Inhibitors].

Using CRISPR/Cas9 technology, the EGFRT790M/C797S mutant fragment was successfully knocked into PC-9 cells to create cell lines harboring the EGFRD19/T790M/C797S mutation. The study demonstrated that the EGFR-TKIs showed different sensitivities to whether the EGFRD19/T790M/C797S mutation was effective or not and different inhibitory effects on the phosphorylation of EGFR and downstream pathways, which demonstrated that this cell line depended on the activation of the EGFRD19/T790M/C797S mutation and EGFR/AKT/MAPK signaling pathway for proliferation. This study provides a clinically relevant cellular evaluation and mechanism validation system for the development of a new generation of innovative drugs targeting EGFR mutation resistance.