Comprehensive data using Next-Generation Sequence (NGS) and fluorescence in situ hybridization (FISH) for detecting MET amplification is limited in Chinese patients, we evaluating NGS performance both in tissue and plasma samples using FISH as reference. We also sought to find optimal thresholds value for NGS in detecting MET amplification via bioinformatics methods.Patients progressed after 1st-, 2nd-, or 3rd-generation (G) EGFR-TKIs were enrolled. Tissue biopsy samples were performed for MET amplification detection via both NGS and FISH. Paired plasma samples were collected for MET amplification detection by NGS. The sensitivity, specificity and agreement were analyzed between NGS and FISH.116 eligible patients were analyzed. 44 patients were male. 82 patients were after 3rd generation EGFR-TKI. MET amplification was detected in 43 (37.1 %) patients by FISH, including 19 (16.4 %) polysomy and 24 (20.7 %) focal amplification. The positive rate of MET amplification in post 3rd generation EGFR-TKI and post 1st/2ndgeneration EGFR-TKI resistant patients was 42.7 % (35/82), and 23.5 % (8/34). The sensitivity, specificity and agreement of detecting MET amplification by NGS in tissue were 39.5 % (17/43), 98.6 % (72/73) and 76.7 % (89/116), respectively, 66.7 % (16/24), 98.6 % (72/73) and 90.7 % (88/97) for focal MET amplification in tissue and 29.2 % (7/24), 94.5 % (69/73), 78.4 % (76/97) for focal amplification in plasma. Results were shown in the table below.NGS is an alternative method for MET focal amplification detection in tissue. While the sensitivity of NGS testing in plasma needs further improvement to maximize identification of patients with potential benefit from dual-targeted therapy.Copyright © 2024 Elsevier B.V. All rights reserved.