LAUSR

e13120Background: The ROS1 rearrangement has been identified in 1%-2% of NSCLC cases, these patients would benefit from the inhibitor of crizotinib. But the resistance to crizotinib inevitably developed in the patients with ROS1+ NSCLC and shown a response to crizotinib initially. The mechanism of acquired resistance to crizotinib for the patients with ROS1+ NSCLC is not identified completely now. In this study, we performed mutational profiling in a cohort of 16 ROS1+NSCLC patients at diagnosis and acquired resistance to crizotinib using targeted NGS. Methods: A total of 16 patients with stage IIIb-IV ROS1+ NSCLC were undergoing tumor biopsies or blood withdrawing by the time of acquiring resistance to crizotinib, including 4 formalin-fixed paraffin-embedded (FFPE) samples, 9 serum samples and 3 serous effusions. We used targeted NGS to detect genes status of patients. Results: In total, we identified 62 genetic alterations with a median of 3.9 mutations per patient. 93% of patients still exhibit fusions...