ROS1 and non-small cell lung carcinoma: Enrichment of plasma ctDNA and incorporation with the next generation deep sequencing techniques allow us to simultaneously detect the gene alterations of interest, e.g. EGFR/BRAF/HER2 mutations, ALK/ROS1/RET rearrangements, MET amplification, etc. in NSCLC, especially when it is difficult to obtain sufficient tissue samples.