ROS1 and non-small cell lung carcinoma: Finally, in a large prospective cohort study involving ALK and ROS1 positive NSCLC patients treated with first to third generation TKIs, a targeted amplicon-based NGS assay revealed the presence of cfDNA alterations potentially correlated with resistance, both in ALK or ROS1 genes and in other genes (i.e., KRAS, PI3KCA, and PTEN).