ROS1 and non-small cell lung carcinoma: The advantage of PDX models for testing of novel targeted therapies for rare, but potentially actionable genomic vulnerabilities has recently been illustrated for both ROS1 and MET mutated NSCLC.28,29 Both of these mutations represent distinct molecular subtypes of NSCLC that frequently metastasize to the brain,30,31 but have not been modeled yet by conventional cell lines.