e13118Background: Major driver mutations of lung cancer are largely considered to be mutually exclusive. Although a few exceptions of coexisting driver mutations have been noted, it is thought that the coexistence of ALK, RET, and ROS1 rearrangements with other major driver mutations is also rare. However, NGS has allowed us to revisit this assumption given the amount of clinical data that are generated. We report findings of the frequency of driver mutations and their coexistence in a cohort of 181 lung cancer patients tested in our laboratory. Methods: A comprehensive molecular- and histopathology-based strategy was conducted on FFPE samples of 181 lung cancer patients. NGS molecular profiling was performed using Molecular Health’s Engineus Profile+ 613-targeted gene panel. For patients diagnosed with adenocarcinoma; ALK, RET, and ROS1 rearrangements were evaluated using FISH method (Personalized Dx, CA). Results: Including both NGS and FISH analysis, major driver aberrations were detected as follows: K...